Antimicrobial resistance develops when micro-organisms evolve different mechanisms to protect themselves from the effects of antimicrobials. Such micro-organisms that develop antimicrobial resistance are difficult to treat and require higher doses or alternative medications that are more toxic to them. When micro-organisms are resistant to multiple antimicrobials, then, they are called multidrug resistant. All classes of microbes, i.e. bacteria, fungi, protozoa, viruses, can develop resistance. The bacteria that are resistant to a wide range of antibiotics are known as extensively drug resistant or superbugs. Antibiotic resistance can be spontaneous as a result of random mutations or can be caused by extensive use of anti-microbials which encourage the selection of mutants that are resistant to them. This book is a valuable compilation of topics, ranging from the basic to the most complex advancements in the field of antibiotic resistance. It covers in detail some existent theories and innovative concepts revolving around antibiotic resistance. This book is a vital tool for all researching and studying this field.