[5] He became a prominent figure in the House of Wisdom, and a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language.

[6] He subsequently wrote hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics, logic and psychology, to medicine, pharmacology,[7] mathematics, astronomy, astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, meteorology and earthquakes.

[11][12] Building on the work of al-Khalil (717–786),[13] Al-Kindi's book entitled Manuscript on Deciphering Cryptographic Messages gave rise to the birth of cryptanalysis, was the earliest known use of statistical inference,[14] and introduced several new methods of breaking ciphers, notably frequency analysis.

[18] Al-Kindi was born in Kufa to an aristocratic family of the Arabian tribe of the Kinda, descended from the chieftain al-Ash'ath ibn Qays, a contemporary of Muhammad.

On account of his learning and aptitude for study, al-Ma'mun appointed him to the House of Wisdom, a recently established center for the translation of Greek philosophical and scientific texts, in Baghdad.

Henry Corbin, an authority on Islamic studies, says that in 873, al-Kindi died "a lonely man", in Baghdad during the reign of al-Mu'tamid (r. 870–892).

Felix Klein-Franke suggests several reasons for this: aside from the militant orthodoxy of al-Mutawakkil, the Mongols also destroyed countless libraries during their invasion of Persia and Mesopotamia.

[24] His greatest contribution to the development of Islamic philosophy was his efforts to make Greek thought both accessible and acceptable to a Muslim audience.

Al-Kindi carried out this mission from the House of Wisdom (Bayt al-Hikma), an institute of translation and learning patronized by the Abbasid Caliphs, in Baghdad.

[26] Al-Kindi took his view of the solar system from Ptolemy, who placed the Earth at the centre of a series of concentric spheres, in which the known heavenly bodies (the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and the stars) are embedded.

One theory he posits in his works is from Aristotle, who conceived that the movement of these bodies causes friction in the sub-lunar region, which stirs up the primary elements of earth, fire, air and water, and these combine to produce everything in the material world.

"[32] This theory of the active power of rays had an influence on later scholars such as Ibn al-Haytham, Robert Grosseteste and Roger Bacon.

On the other hand, Euclid proposed that vision occurred in straight lines when "rays" from the eye reached an illuminated object and were reflected back.

On the other hand, Euclidean optics provided a geometric model that was able to account for this, as well as the length of shadows and reflections in mirrors, because Euclid believed that the visual "rays" could only travel in straight lines.

For example, he developed a mathematical scale to quantify the strength of a drug, and a system (based on the phases of the moon) that would allow a doctor to determine in advance the most critical days of a patient's illness.

[38] One work attributed to al-Kindi, variously known as the Kitāb al-Taraffuq fī l-ʿiṭr ("The Book of Gentleness on Perfume") or the Kitāb Kīmiyāʾ al-ʿiṭr wa-l-taṣʿīdāt ("The Book of the Chemistry of Perfume and Distillations"), contains one of the earliest known references to the distillation of wine.

[39] The work also describes the distillation process for extracting rose oils, and provides recipes for 107 different kinds of perfumes.

[42]Al-Kindi was influenced by the work of al-Khalil (717–786), who wrote the Book of Cryptographic Messages, which contains the first use of permutations and combinations to list all possible Arabic words with and without vowels.

"[43] In order to support his argument, he gave a description of a scientific experiment as follows: One can also observe by the senses... how in consequence of extreme cold air changes into water.

[6] His own thought was largely influenced by the Neo-Platonic philosophy of Proclus, Plotinus and John Philoponus, amongst others, although he does appear to have borrowed ideas from other Hellenistic schools as well.

[51] Experts have suggested that he was influenced by the Mutazilite school of theology, because of the mutual concern both he and they demonstrated for maintaining the singularity (tawhid) of God.

[57] Al-Kindi says that the soul is a simple, immaterial substance, which is related to the material world only because of its faculties which operate through the physical body.

To explain the nature of our worldly existence, he (borrowing from Epictetus) compares it to a ship which has, during the course of its ocean voyage, temporarily anchored itself at an island and allowed its passengers to disembark.

Here, al-Kindi displays a stoic concept, that we must not become attached to material things (represented by the island), as they will invariably be taken away from us (when the ship sets sail again).

He argued that, through the faculty of "imagination" as conceived of in Aristotelian philosophy, certain "pure" and well-prepared souls, were able to receive information about future events.

Significantly, he does not attribute such visions or dreams to revelation from God, but instead explains that imagination enables human beings to receive the "form" of something without needing to perceive the physical entity to which it refers.

[61] While al-Kindi appreciated the usefulness of philosophy in answering questions of a religious nature, there would be many Islamic thinkers who were not as enthusiastic about its potential.

[62] During his life, al-Kindi was fortunate enough to enjoy the patronage of the pro-Mutazilite Caliphs al-Ma'mun and al-Mu'tasim, which meant he could carry out his philosophical speculations with relative ease.

His works, says Deborah Black, contained all the seeds of future controversy that would be fully realized in al-Ghazali's Incoherence of the Philosophers.

Ibn al-Nadim in his Kitab al-Fihrist praised al-Kindi and his work stating: The best man of his time, unique in his knowledge of all the ancient sciences.