J. LENNART BERGGREN is Professor of Mathematics at Simon Fraser University and twice president of the Canadian Society for the History and Philosophy of Mathematics. His previous books include Episodes in the Mathematics of Medieval Islam and Pi : A Source Book. ALEXANDER JONES is Professor of Classics and of the History and Philosophy of Science at the University of Toronto. He studies the history of the exact sciences in antiquity. He is the author of Pappus of Alexandria : Book 7 of the Collection and Astronomical Papyri from Oxyrhynchus.