The investigation of discrete symmetries is a fascinating subject which has been central to the agenda of physics research for 50 years, and has been the target of many experiments, ongoing and in preparation, all over the world. This book approaches the subject from a somewhat less traditional angle: while being self-contained and suitable to the reader who wants to acquire a solid knowledge of the topic, it puts more emphasis on the experimental aspects of the field, trying to provide a wider picture than usual and to convey the intellectual challenge of experimental physics. The book includes the related connection to phenomenology, a purpose for which the precision experiments in this field - often rather elegant and requiring a good amount of ingenuity - are very well suited. The book discusses discrete symmetries (parity, charge conjugation, time reversal, and of course CP symmetry) in microscopic (atomic, nuclear, and particle) physics, and includes the detailed description of some key or representative experiments. The book discusses their principles and challenges more than the historical development. The main past achievements and the most recent developments are both included. The level goes from introductory to advanced. While mainly addressed to graduate students, the book can also be useful to undergraduates (by skipping some of the more advanced sections, and utilizing the brief introductions to some topics in the appendices), and to young researchers looking for a wider modern overview of the issues related to CP symmetry.