Alexander's essay on the conversion of predicative propositions contains otherwise unknown information about the early history of Aristotle's logic. The essay survives only in a mutilated Arabic translation. This volume contains a new edition of the text, a translation (the first into any modern language), and a discursive commentary. It will be of interest to anyone concerned with the history of Aristotelianism or with the history of logic.

Thomas Auffret, Jonathan Barnes, Marwan Rashed, Sorbonne University, Paris, France.