The General Microbiology Course is designed for students of the Licence 1 in Biochemistry and the Licence 2 in Biology and Medical Biology. Microbiology is a fundamental science that studies the structure, physiology and ecology of microorganisms. The term (microbe) encompasses all living organisms, small in size and requiring the microscope to observe them. It includes fungi (molds and yeasts), unicellular algae, protozoa, bacteria and viruses. The place of micro-organisms in the living world. After the discovery of microorganisms, scientists tried to classify them as living beings with the development of Molecular Biology techniques. Woese CR and then Haeckel proposed more precise classifications based on objective and phylogenetic criteria. In 1866, E. Haeckel divided the living world into three kingdoms: animals, plants and protists (algae, protozoa, fungi and bacteria).