A number of techniques are routine in microbiology laboratories that enable microorganisms to be cultured, examined and identified. Microbiology can be defined as the study of organisms too small to be seen with the naked eye. Shows the relative size of microbes compared to other living things. However, the recent discovery of bacteria of near 1 mm in size has made this definition somewhat inaccurate and in the grand tradition of science, a new definition is in order. Microbes for being small, span a large of sizes from the T4 virus that are 0.02um to giant bacteria larger than 700um. Techniques also help detect the presence of bacteria that have become altered in their structure or genetic composition. The technique of replica plating relies on the adhesion of microbes to the support and the transfer of the microbes to a series of growth media. The technique is analogous to the making of photocopies of an original document. The various media can be tailored to detect a bacteria that can grow in the presence of a factor. Such as an antibiotic. That the bacteria from the original growth culture cannot tolerate. Bacteria and fungi are growth on or in microbiological media of various types. The medium that is used to culture the microorganism depend on the microorganism that one is trying to isolate or identify. Different nutrients may be added to the medium, making it higher in protein or in sugar. Various PH indicators are often added for differentiation of microbes based on their biochemical reactions. Other added ingredients maybe growth factors, NaCI, and PH buffers. The text concentrates on the essential aspects of microbiology and thus provides the student with a broadly based overview of the subject. The book includes new species, mew phylogenetic relationships and a greater emphasis on environmental and ecological matters.