Running through the articles in this volume is the theme of the appropriation and subsequent naturalization of Greek science by scholars in the world of medieval Islam. The opening paper presents the historiography of this process, and the focus is then placed on Ibn al-Haytham, one of the most original and influential figures of the 11th century, and in particular in his contribution to the science of optics, both mathematical and experimental, and the psychology of vision. Professor Sabra then continues the analysis of how Greek thought was developed in the Islamic world with two studies of work based on Euclid's geometry and two on critiques of Ptolemaic astronomy. The final articles turn specifically to questions in the history of logic - Aristotelian syllogism, and Avicenna's views on the subject - matter of logic.