Atrial Fibrillation; a common heart disorder, is the focus of this book. The book is intended to give a complete evaluation and introduction of Atrial Fibrillation. This book contains several chapters divided into distinct parts according to its respective functions. It explains the fundamental mechanisms of initiation and maintenance of atrial fibrillation. Then, it discusses mapping of atrial fibrillation and new techniques of signal detection. Clinical prognostic and remodeling is also revised thoroughly within the book. Furthermore, it describes universal evaluations of catheter-based/surgical dealing and treatment of the disorder. Finally, it deals with atrial fibrillation in precise situation and its difficulties.