This book is a selection of Microbiology organized in a logical sequence of topics starting with different aspects, progressing through structure, physiology and taxonomy of pathogenic microbes such as Bacteria, Fungi, Viruses, and Parasites. It is indented as an examination guide in medical microbiology for students of microbiology and biotechnology seeking admission in Postgraduate Courses and other competitive examinations. The material of this book is essentially based on recent achievements in the domain of microbiology, and to its credit many standard textbooks and many individual articles were consulted while writing the manuscript.