This book provides the reader with a comprehensive account of the contributions of Pythagoras to mathematics and philosophy, using them as a starting point to compare pre-Pythagorean accomplishments with the myriad mathematical developments that followed. It begins with a thorough study of Pythagoreanism and the early Pythagoreans, including the major events in Pythagoras' life and the origins of the mystical significance attributed by Pythagoreans to natural numbers. From Chapter 3 onward, the book describes how mathematical thinking works and prepares the reader for the subsequent chapters, which cover mathematical logic and proofs, their application to the study of natural and prime numbers, the investigation of Pythagorean triples, figurative numbers, and irrational numbers, all interwoven with rich historical context. Aimed at students and teachers at all levels, this work is accessible to non-mathematicians as well, with the main prerequisite being an avid curiosity about some of the ideas and thinkers that helped to forge the mathematical world as we know it.   Early praises for “Mathematics Before and After Pythagoras”: “Your book is charming and fun to read. It would be fine to be able to teach from it.” (Steve Krantz, USA) “...your new book, an obvious labor of love... I can see that it will be an inspiration for young students.” (Bruce Berndt, USA) “It is an excellent book, and I am deeply grateful for sending it to me. It is an extraordinary gift, and I am so grateful for this.” (Carlo Cattani, Italy) “I am really impressed by the wealth of interesting material you have collected and presented.” (Rainer Kress, Germany)