This book is something of a classic of the literature of the history of mathematics. It deals not with the men and women who made mathematics their life and work but with those significant figures who were primarily known for some other activity yet whose contributions to mathematics were of permanent value. With this lucid and hugely enjoyable survey, Professor Coolidge attempted to evaluate their mathematical discoveries in the light of what was known about their lives and circumstances. First published in 1949, it remains a valuable and highly scholarly introduction to these figures. Inevitably, modern scholarship has thrown new light on the subjects of this book. Rather than disrupt the overall flow of the book which is produced here unchanged, Professor Jeremy Gray has provided a short biographical note about Professor Coolidge and an introductory essay which discusses where new historical and mathematical material is now available. Thus, Professor Gray is able to describe both the strengths and flaws of this account and to discuss the new ways in which the history of mathematics is being re-evaluated.