Book excerpt: Bacteria constitute a large category of prokaryotic microorganisms which are a few micrometers in size. The study of bacteria, their biochemistry, morphology, ecology and genetics is under the scope of bacteriology. The importance of bacteriology is witnessed in its wide applications in the treatment and prevention of diseases with the use of vaccines. It is an important domain under microbiology, which studies the classification, identification and characterization of bacterial species. This textbook aims to shed light on some of the unexplored aspects of bacteriology. It elucidates new techniques and applications of this discipline in a multidisciplinary approach. In this book, constant effort has been made to make the understanding of the difficult concepts of bacteriology as easy and informative as possible, for the readers.