This book is for physicists, historians and philosophers of physics as well as students seeking an introduction to ongoing debates in relativistic and quantum physics. This title is unique in that: - it comprises contributions by leading physicists, philosophers and historians of science; - it covers the recent debates on the emergence of relativity and quantum theory; - it includes chapters with an introductory character, comprehensible to students and science teachers; - it can be used in graduate level courses in the history and philosophy of science; - it strengthens the bonds between the communities of scientists, historians, and philosophers.