Fascination with the heavens, coupled with the need to determine the timings of prayers and direction of Qibla in diverse locales, resulted in the tremendous development of Astronomy from the very beginning. The progress took place along three interlinked pathways - development of infrastructure; collection of data; and interpretation of data in conjunction with original theoretical models. First path entailed construction of royal and private observatories - at Baghdad, Damascus, Maragha, and Samarqand etc…...and designing of several new instruments by highly creative innovators of the era, to felicitate observations. In this regard, a very important invention was Astrolab designed by Jandab an eighth century scientist.
Al-Battani, Ali Bin Isa and others developed and perfected it to such an extent that it became an instrument of observation and a kind of computing device for calculating complicated trigonometric functions and for determining astronomical parameters/functions. Through it, they could tell the date and hour from the position of certain stars. Movable sights on the instrument were aligned with the star and relevant numbers and signs were read off from windows in the instrument or from its circumference.
Al-Khujandi constructed another very useful device, called Sudus al-Fakhri. It is now known as Sextant. Farghani, another inventor developed and improved the Sun dial known to Greeks and Babylonians. All these devices were revolutionary inventions of their time and with the help of these instruments, astronomers collected data. They carried several observations to determine Obliquity ‘i’ and the eccentricity ‘e’, compiled tables of all kinds.
Thus by ninth century, a team working under Yahya Mansoor, the director of Al-Mamun Observatory, had made a number of astronomical observations and another team which had been given the task of determining the value of one terrestrial degree, managed to measure the radius of the earth from this observation, with only a 2.5% error. By eleventh century, Al-Bairooni using a different method reduced this error to 0.25%. Boozjani: [1011 AD] proved that sun had attraction; this attraction affected moon’s orbit and that it did not exceed 1º 15’. Al-Battani, one of the great mathematicians and astronomers of the world, discovered the correct angle of inclination of earth; proved the ‘Trepidation of Equinoxes’ as being a wrong concept; proved that the orbit of the earth is not circular but elliptical; prepared Astronomical tables known as ‘Zij Al-Battani’ that were of immense value to Astronomers of the 9th and 10th centuries. The list of eminent astronomers of this era and their works is simply too long to narrate here.
After thoroughly studying the Greek theoretical model of the planetary motion and its modification given by Ptolemy, astronomers like Al-Bitruji, Al-Tusi and Qutubuddin Shirazi etc. propounded their own models, while some others like Ibn Al- Shatir suggested further modifications in the Ptolemic model. In fact, Copernicus in his famous book has used what is known today as Al-Tusi’s device for producing linear motion as a resultant of two circular motions. The famous historian W. Hartner has proved even the fact that the geometrical figure of this device as produced by Copernicus, is exactly identical even to the extent of the lettering employed by Al-Tusi in his Arabic astronomical treatise. And it was this device that played a very important role in the development of an alternative non-Ptolemic model of planetary motion.
The greatest contribution of these scholars is in mathematics. They founded Algebra; made Trigonometry an independent branch of mathematics; and achieved tremendous advances in other fields like Geometry and spherical geometry etc. In this case too the impetus for the development was provided by the Message. Al-Khwarizmi the founder of Algebra, was the first mathematician to work on the details of ‘Arithmetic and Algebra of inheritance’ besides the systematisation of the theory of quadratic equations. His treatise entitled ‘Hisab Al-jabr wal muqabala’, enjoyed tremendous popularity in the medieval West for centuries. Tabit ibn Qurrah of ninth century, who had translated the works of Euclid, Apollonius, Archimedes, and Ptolemy was another fine mathematician himself. The only surviving fragment of his original work contains an exceptionally brilliant chapter on the solution and properties of cubic equations.
Umar Khayyam, the famous poet, was another great mathematician. He invented the second and third degree of quadratic equations. The efforts of these mathematicians become all the more remarkable when we realise that they had not yet developed the symbolic algebra. Even for third degree equations, Khayyam had to write his problems and procedural steps in words and sentences.”
The algebraic symbols were introduced quite late. Al-Banna and Al-Marrakushi used them in thirteenth and fourteenth century. Later mathematicians like Qunfudh’s and Al-Qalasadi’s works of fourteenth and fifteenth century show quite a developed system of symbols for operations entailing extraction of square roots, exponentiation, and for unknown quantities in algebraic equations.
The numerals and the decimal notation used today originally came from India but these scholars gave them a much more explicit, simple and easy to use form, than the highly cumbersome Roman numerals, which it ultimately replaced. The development of Trigonometry, Spherical Trigonometry and Geometry also show the intensely original creative work done by these scholars. Here too the concepts of Sine and Cosine came from India, but Habsh Al-Hasib and Al-Battani extended them to other Trigonometrical ratios, like tangent, secant and their reciprocals. It was Al-Battani, who had derived this formula:
sin a = tan a / Ö (1+tan²a) and Cosa = 1 / Ö(1 + tan²a).
Later Al-Nayrizi, Abul Wafa, Al-Khujandi and Abu Nasr Mansur etc. helped develop this branch. It was Abul Wafa who had given this famous formula:
sin (a + ß) = sin a cos ß + sin ß cos a.
Abul Wafa had also discussed the quadrature of the parabola and the volume of the paraboloid. Yet trigonometry remained mainly the work of Al-Battani, Al-Bairooni and Al-Tusi etc. For the degree of accuracy in mathematical works, Jamshed Al-Kashi tops the list. He gave the value of p up to 16 decimal places and of Sine 1° up to 18 places.
I must also mention two other mathematicians of this era, whose contributions were quite revolutionary in content. Ali Ahmad Nasawi who died in 1030 AD, studied an alternative Indian system of time division based on 60. Indians had divided the day into 60 Ghatika. One Ghatika into 60 pal and one pal into 60 bapal. Thus one pal was equal to 24 seconds and one Ghatika or Ghari was equal to 24 minutes. Nasawi revolutionised this system, by dividing the day into 24 Saat, one Saat into 60 Daqeeqa and each Daqeeqa into 60 Sania. It was this division of time that was taken by rest of the world as standard. In the language of Message Daqeeqa means a small or minute quantity and Sania means second or the other unit. Thus we can see that the terms ‘minutes and seconds’ are exact translations of the original words used by Nasawi. Moreover, he also worked on the decimal system and made complete conversion charts between both the systems.”
Masalima al-Majriti, an expert mathematician, zoologist and chemist of tenth century, was the World’s first economist. From eighth century till thirteenth century, ‘followers of the Message’ were dominating the world’s economic scene. The entire known world was either trading with them or through them. Majriti studied markets, commercial transactions, different types of businesses and associated traditions. After that he laid down exhaustive guidelines, rules and laws for the entire commerce. He organised the information, rules, and laws in such a manner that after him commerce became a separate subject by itself. Besides commerce, he also studied zoology and prepared an exhaustive book on species of animals, their characteristics and observation about their habitats. His third interest was chemistry and on this subject too, he left a standard work.
The next important field where this civilisation showed its most sustained effort was medical science. General medicine, pharmacy, ophthalmology, surgery and gynaecology, all received attention from their researchers. One of the brightest star of this era was Mohammed Zakaria Razi . An astronomer, philosopher, botanist, physicist and physician par excellence, Razi contributed immensely to the development of medical science. He not only improved the working of several hospitals of Baghdad but also established a new hospital with a streamlined procedure, devising a way to check pollution of the area.
The pollution was checked by placing pieces of meat at all the proposed sites for the new hospital. After three days, the site where the meat showed least deterioration was selected. In this hospital the patients were first screened by a batch of doctors and those with serious and complex diseases were sent to Razi. He studied them, suggested medicines, observed the progress and noted every change and its effect exhaustively. Thus he experimented on hundreds and thousands of herbs and plants; and placed them in suitable categories in a book, which can be called the first medical encyclopaedia. He also wrote ‘A Treatise on the Small Pox and Measles’. This treatise contains the first clear description of the major symptoms of the two diseases. The concept of ‘First Aid’ was introduced by him for the first time. He also invented the Hydrostatic Balance to measure small quantities and designed several surgical instruments.
Another contemporary of Razi, who has several firsts to his credit was Sinan bin Thabit Harrani . Prior to his time there was no standardization and no law regulating the practice of medicine. Being in charge of administration and an expert physician he introduced numerous laws to regulate the practice of medicine. He was the one who invented the system of examination and registry of medical practitioners with the government for the first time in the world. He also produced guidelines for medical students; instituted numerous improvements in the hospital administration; launched mobile hospitals for the first time and introduced medical check-up and treatment of prisoners.
First Gynaecologist of the world, Qartabi’s  research was on pregnancy; embryology; mother and child; and pre and post natal care. He was also a philosopher, historian and botanist. Another pioneer of the same time was Abul Qasim Zahrawi. He introduced the technique of surgery in the treatment of diseases. In his book he has emphasised cleanliness and sophistication in the operation and laid down guidelines and rules for surgical operations. He was also the inventor of more than 100 surgical instruments.
In Ophthalmology, although Amar Mansuli introduced the technique of surgery in eye diseases, it was Ali bin Isa who provided the world detailed information on this subject. His book, which is in three parts, is virtually an Encyclopaedia on Ophthalmology. There are a total of 130 eye diseases listed in this book; 143 herbals and medicinal plants beneficial for the eye and hundreds of precautions, and the type of food to keep the eyesight healthy. The other big names of Ophthalmology were Caliph Ibn-Ali-Al-Mahasin , who had an unrivalled reputation for removing cataracts even in cases when one eye was already lost and Al-Shahdili , whose Kitab al-umda also contains details regarding the development of Trachoma and the description of Cancer of the eyelid.
Another Ophthalmologist, Ibn Nafis Al-Qurshi  brought a revolution in the Medical science by discovering the ‘Pulmonary Blood circulatory system’ of the body, which was known in the medieval world as ‘lesser circulation’, almost 300 years before Harvey and Survetus, who are credited with this discovery. Another revolution was brought by two contemporary researchers. Ibn Khatima , who has left in his writings, description of extremely small agents that he thought were responsible for diseases. And Ibn al-Khatib , the writer, poet, historian, politician, geographer, philosopher and a great physician who, working independently, differentiated the diseases into Infectious and non-infectious category, and presented the novel concept that invisible insects seemed responsible for Infectious diseases. He named them Gerasemes. A word that later got converted into germs.
Then men like Abdul Lateef Baghdadi [1162-1231] and Mansoor bin Mohammed have contributed greatly to the study of human anatomy. In this regard, the book on Anatomy written by Mansoor, in 1396, is still extant.
This world of medicine went hand in hand with the researches in Pharmacy and Botany also. Abu Mansur Harawi  was an expert Botanist, who divided the medicines into organic and inorganic category. His book contains a total of 585 medicines - 510 in the organic category and 75 in the inorganic category.
In the field of zoology, Abdul Malik Asmaee , was a pioneer who wrote five books on this subject, describing the life of the forest through the animals’ perspective. These books have the distinction of being the first on this subject. Another important contributor to this field, a multifaceted genius was Ibn Maskoya . Philosopher, intellectual, critic, historian, biologist, sociologist, psychologist, researcher on ethics, metaphysics, rural and urban civilisation etc.. He was the first scientist to suggest relationship and grades in the entire kingdom of living beings, including plants, animals, and human beings.
We do not mean to belittle Darwin’s enormous efforts in the collection of all the data and its interpretation, but as far as the evolution of the ‘concept of evolution’ is concerned, a part of the credit should also be given to Farabi and Maskoya, specially Maskoya. Some of his tremendous output is still available, and can be studied to prove or disprove this claim.
Optics was one such branch. And although several great names were associated with this field, Ibn Al-Haithem, known to West as Alhazen, easily tops the list. In fact, his contribution to this branch of physics is so tremendous and revolutionary that H.J.J. Winter, a British Historian had described him as ‘After Archimedes (287-212 BC) no really great physicist appeared until Ibn Al-Haithem (965-1039 AD)’ Ibn Al-Haythem provided the proof of the specular reflection and complete formulation of laws of reflection. He also designed and used a copper instrument to measure reflection from plane, spherical, cylindrical and conical mirrors and also from paraboloidal surfaces. His theories about spherical aberration, focus, foci and his method of determining the location of images were quite ahead of his time. He also made improvements to the Ptolemaic apparatus to measure accurately the refraction of the ray of light, through air, glass and other mediums, thus discovering a large number of relationships, between the angles of incidence, refraction and deviation. These discoveries benefited humanity tremendously and ultimately paved the way for Snell’s Sine-law of refraction. A German science historian, Mathias Schramm, has suggested that in his lectures, Snell had depended to a large extant on a treatise of optics, which was jointly written by Petras Ramus and Friedrich Risner and was published after their death at Kassel, Germany, in 1606. Friedrich Risner, in turn, was much influenced by Al- Haythem’s treatise on optics, which he had also edited and published in 1572, eight years before his death in 1580. Thus the connection seems obvious. Al-Haythem’s numerous other findings too are revolutionary. He had declared that ‘light’ is an essential characteristic of self luminous bodies, diverging totally from Aristotelion physics. He had also distinguished between light from source as primary, and reflected light from bodies as secondary, and proved that moonlight was reflected light from the sun. Moreover, studying shadows of objects and solar and lunar eclipses, he showed that emission of light takes place ‘in the form of a sphere’, rectilinearly in all directions. He was also the first to consider velocity of light to be finite, too quick to perceived by senses, and easier and quicker in rarer mediums and slower in denser mediums. Surprisingly, this concept forwarded in 1000 AD, has been found to be correct, while Newton of a much later date was wrong. Then Al-Haythem also studied atmospheric refraction, rainbow, twilight and physiological optics. His extant manuscripts, include a major work on vision and numerous theories, explanations and experiments etc.
Chemistry was another product of this period. One of the greatest names of this field was Jabir bin Hayyan , who can rightly be called ‘Father of Chemistry’. He was the first scientist who gave preference to experiments and laid down rules and methodology for experiments, which are still in use. Among his discoveries and inventions are - the process of crystallisation, sublimation and distillation; the way of filtration; different type of salts; several new metallurgical processes; phenomenon of oxidation; a way for waterproofing cloth; a way for colouring leather; the invention of hair dye; invention of sulphuric acid, Nitric acid and Aqua Regia; and a way to turn iron into steel. The name was not given by him. The contents and description of the action of the acid, identifies the product.
The first recorded geologist, who was also a metallurgist and a Calligraphist, belonged to this era. His name was Attar Al-Katib. He had collected thousands of different varieties of stones and recorded his observations and experiments in a book. The science of writing Encyclopaedias also started with this civilisation. The first man to compile all the available information regarding all branches of science in an alphabetical order was Mohammed Bin Ahmad Khwarizmi. This method was later adopted universally for writing the modern Encyclopaedia. Prior to him all such books listed the information subject wise.
Ibn Batuta and Al-Idrisi, studied lands, continents, climate and weather patterns and organised all their observations and experiments into a science which later became known as geography, improving tremendously upon Ptolemy.
In those days, Arab navigators were dominating the world’s naval scene. Idrisi correlated and organised all the data, made world maps and wrote several books on this subject. He discovered the source of Nile which has been shown on his map of Africa.
People like Ibn Rushd popularly known as Avverros, in whose name a movement had started in the West; or Shaikh bu ali-Sina who is known as Avicina - the greatest benefactor of medicine of medieval west; Al-Bairooni, the multifaceted genius, who introduced India to the West, besides contributing immensely to astronomy, physics, astrology, history, mathematics and other branches; or Ibn Khaldun - the first sociologist of the world, an all time great historian and a man who is credited to have the maximum information in the world at the time..”
The Observatories in Islam, - A. Sayili, Publications of the Turkish Historical Society Series VII, No. 38, 1960.
Obliquity i is the angle between the plane of earth's orbit and the celestial equator.
The orbit of the earth is not a circle but an ellipse. The sun is not at its center but at one of its foci. The shape of this ellipse is characterized by this quantity. The Obliquity of the Ecliptic, Astronomy and Astrophysics - A. Wittmann, (Berlin), 73 (1979), pp.129-131.
 It is called Evection. Tych Brahe in 16th. century corroborated this view. JA
 R.A. Ansari's work - p 46.
 Fuat Sezgin, in his History of Arabic-Islamic Mathematics [Vol v, Leiden 1974] lists 155 Arab Islamic Mathematicians upto 11th. century only. The bibliography of Al-Biruni's comprises of 183 works and that of Ibn Al-Haitham of about 100 scientific works.
 The laws of inheritance needed the development of operations for handling fractions.
The word `Algorithm or Algorism' is the distorted version of his name. He died in 850 CE. Of the three mathematicians considered all time greats in the medieval world, two of them were Al-Khwarizmi and Al-Battani.
The Algebra of Omar Khayyam, translated with commentaries by Daoud S. Kasir.
This book was so popular in the west that between 1486 and 1542 the Latin translation of such massive work was printed five times.
 This treatise has been reprinted more than forty times during the last four hundred years.
The Emergence of the Prototype of the Modern Hospital in Medieval Islam, - A. Sayili, Proceedings of the Intern. Congress on the Hist. And Phil of Sci, published in journal of Central Asia, Vol.III, No.2 (1980).
 His three books containing exhaustive data related to his researches were the first books on Gynaecology in the world. An expert Botanist, he wrote another book on herbs and plants. He also wrote on the history of Cardova.
 His book entitled `Tasreef' is the most complete book on this subject.
 First Latin translation came in 1499 AD; French edition in 1903 and German edition in 1904.
 His Kitab al-kafi fi al-kuhal - “The sufficient treatise on collyrium”, contains a systematic account of the anatomy of eye, its diseases and treatment, including detailed discussion of some surgical operations.
 He had written a total of sixty books, out of which 20 are available.
 Inorganic category contains some very important drugs like Sodium and potassium Carbonates and Antimony and Silicon oxide etc. He also pointed out that Copper and Lead compounds are poisnous and another compound, which is now known as `Plaster of Paris' should be used on broken bones.
This concept is known to us today as Huygen’s principle.
 Chemistry is a derivative of Al-chemi, a discipline which started out of a wish to turn any metal into gold.
 He noticed for the first time that weight of metal increases after burning.
 Suhal Bin Aman and Ibn Majid were called Asadul-bahar or Captain of the oceans.