Gerard studied in Toledo, Spain.
Gerard devoted all his life to making Latin translations from the Arabic scientific literature. His Latin translation of the Arabic version of Ptolemy's Almagest made about 1175 was the most widely known in Western Europe before the Renaissance. Unbeknownst to Gerard, an earlier translation of the Almagest had already been made in Sicily from the original Greek in 1160 under the aegis of Henricus Aristippus, although this version was not as widely used in the Middle Ages as Gerard's version. The Almagest formed the basis for Western astronomy until it was eclipsed by the theories of Copernicus.
Gerard edited for Latin readers the Tables of Toledo, the most accurate compilation of astronomical data ever seen in Europe at the time. The Tables were partly the work of Al-Zarqali, known to the West as Arzachel, a mathematician and astronomer who flourished in Cordoba in the eleventh century.
Al-Farabi, the Islamic "second teacher" after Aristotle, wrote hundreds of treatises. His book on the sciences, Kitab lhsa al Ulum, discussed classification and fundamental principles of science in a unique and useful manner. Gerard rendered it as De scientiis (On the Sciences).
Gerard translated Euclid’s Geometry and Alfraganus's Elements of Astronomy. He also composed original treatises on algebra, arithmetic, and astrology. In the astrology text, longitudes are reckoned both from Cremona and Toledo.
In total, Gerard of Cremona translated 87 books from the Arabic language, including such originally Greek works as Ptolemy's Almagest, Archimedes' On the Measurement of the Circle, Aristotle's On the Heavens, and Euclid's Elements of Geometry. Gerard of Cremona was also the creator of anatomical terms.