In recent decades we have begun to realize that the microbial world is very diverse, that microbes can exist in the most extreme environments, and that the number of fungi, unicellular protists, bacteria, archaea, viruses and viral-like particles; It outnumbers plants and animals by a wide margin. Today we know that microbes play a central role in ecosystems, in the chemistry of the atmosphere and oceans, and inside our bodies. Microbiology, supported by modern techniques derived from molecular biology, has become one of the fastest growing and active branches of science.

In this very short introduction, the author takes us on a quick trip to microbiology, explains its importance among the vital sciences, describes contemporary understanding of a wide range of microorganisms, and considers the pivotal role that microbes play in ecosystems and the human body, as well as explores many Important applications of microbiology in medicine, agriculture and biotechnology.