An antibiotic is an antimicrobial substance which is used in the treatment and prevention of bacterial infections. It can either inhibit the growth of bacteria or kill them. It may be prescribed as a preventive measure to at-risk populations. These may include those with a weakened immune system or taking immunosuppressive drugs, or those undergoing surgery or affected by cancer. It is also used in surgical procedures for preventing infections of incisions, and in dental antibiotic prophylaxis for preventing bacteremia and subsequent infective endocarditis. Antibiotics can be classified as bactericidal and bacteriostatic. Bactericidals kill bacteria directly whereas bacteriostatics prevent bacteria from dividing. Antibiotics are also classified on the basis of target bacteria. They can be produced through synthetic and semi-synthetic methods. Evidence suggests that bacteria are increasingly developing resistance to antibiotics, which makes research, development and production of new antibiotics pertinent. This book brings forth some of the most innovative concepts and elucidates the unexplored aspects of antibiotics. It presents researches and studies performed by experts across the globe on the characterization and production of antibiotics. With state-of-the-art inputs by acclaimed experts of this field, this book targets students and professionals.