Antibiotics are among the most frequently used drugs all over the world and in our country. Antimicrobialtreatments are constantly being updated due to emerging agents and resistance to known agents. In this book, itis aimed to review the principles of antimcrobial treatment and also to describe the action mechanisms, usageareas, side effects and clinical uses of antibacterial agents. This book addresses all physicians, especially infectiousdiseases and clinical microbiology specialists. The book includes 20 chapters prepared by 17 authors. Iwould like to thank all my colleagues who contributed to the preparation of the book. I would also like to thankKutay Berk Gül for his contribution in the cover design. We hope the book will be useful to all physicians.