These scholars left behind a rich legacy. Greek philosophical tracts from Aristotle and Plato were translated into Arabic as were ancient Persian and Indian "wisdom literature" texts.
'Abbasid scholars also made significant advances in mathematics, building upon earlier work by Indian, Iranian, and other Asian scholars. Parts of modern algebra, decimal fractions, exponents, and the numeral system are part of this rich legacy of scholarship.
Arab scientists developed a theory that illnesses were caused by small organisms and not by curses or bad omens as was believed in Europe at that time. Mental illness was treated as a disorder and not as possession.
'Abbasid Herbal Pharmaecology Text
'Abbasid Anatomy Texts
Sophocles (left) pictured in an Arabic Translation Text
Aristotle pictured in an Arabic Translation Text
An EXCELLENT source for further readings on the subjects described above: http://www.al-bab.com/arab/science.htm
Islamic Sciences and the Making of the European Renaissance (Georges Saliba)
The Legacy of Islam: 2nd Edition (C.E. Bosworth; Joseph Schacht)