This book tackles important questions which have engaged mathematicians and philosophers for thousands of years and are still being asked today. The main purpose of the book is to ask: In what sense do mathematical objects exist? How can we have knowledge of them? Why do mathematicians think mathematical entities exist for ever, independent of human action and knowledge? In clear, elegant prose and with scholarship born of first-hand experience, Reuben Hersh illuminates the mysteries behind the meaning and nature of mathematics.