Infectious diseases are accountable for more than millions of deaths every year throughout the globe. Among them, significant contributors are protozoan parasites. Despite the many research group working on the various protozoan diseases, there are still major gaps to fill. The authors of this book have critically reviewed all the aspects of major protozoan diseases, their diagnostics, and treatments including resistance. This book comprises twelve chapters, and chapters are discussed about each major protozoan disease such as Malaria, Leishmaniasis, etc., including clinically minor protozoan disease. This book provides all essential information to the professional researcher and medical personnel about the disease, causative organism, and their life cycle, diagnostics, treatment including drugs and vaccine, resistance, and key points of future research.