A microbe is any microscopic organism, esp., a bacterium or microzyme, causing disease or fermentation. Microbiology is the branch of Biology involving the study of microorganisms and their effects on man. These organism are generally too small to be seen with naked eyes. They are important as wells harmful for human life. As for their benefits, they are essential for the immune system of the body as they defend the body. Obviously, their absence in the body leads to the breakdown of the immunity of the body. Similarly, these micro-organisms are equally important for preparing any types of dishes. For instance, curd and cheese are prepared because of them. On the other hand, they play the role of disease-carriers and cause malaria, soaring of the throat and cold, etc. This encyclopaedia talks of all these minute living organisms at length. Prepared with utmost care, it would, hopefully, prove to be of great help to the students of Microbiology and the scholars thereof equally.