Nathan Sidoli is a professor of the history and philosophy of science at Waseda University, Tokyo. He has published widely on Greek and Islamic mathematics and astronomy, including Thābit ibn Qurra’s Restoration of Euclid’s Data, with Yoichi Isahaya, and is currently co-editor of Historia Mathematica and SCIAMVS. R.S.D. Thomas is an emeritus professor of mathematics at the University of Manitoba and fellow of St John's College in Winnipeg, Canada. His previous historical work was Euclid’s Phaenomena, with J.L. Berggren. His main scholarly activity since 1992 has been editing the journal Philosophia Mathematica.