Industrial microbiology and industrial biotechnology have enormous versatility involving microbes, mammalian cells plants, and animals. It encompasses the microbial production of primary and secondary metabolites and small and large molecules from plants and animals. Amino acids, nucleotides, vitamins, solvents, and organic acids comprise the primary metabolites. Multibillion-dollar markets are involved in the production of amino acids. Fermentative production of vitamins is replacing many synthetic vitamin-production processes. In addition to the multiple reaction sequences of fermentations, microorganisms are extremely useful in carrying out biotransformation processes. Multibillion-dollar markets exist for the medically useful microbial secondary metabolites, i.e., 160 antibiotics and derivatives such as the β-lactam peptide antibiotics, glycopeptides, lipopeptides, polyketides, aminoglycosides, and others. The anti-infective market amounts to 55 billion dollars. Secondary and primary metabolites are of great importance to our health, nutrition, and economics. Enzymatic and cell-based bioconversions are becoming essential to the fine chemical industry, especially for the production of single-isomer intermediates. Microbes also produce hypocholesterolemic agents, enzyme inhibitors, immunosuppressants, and antitumor compounds, some having markets of several billion dollars per year. They also make agriculturally important secondary metabolites such as coccidiostats, animal growth promotants, antihelmintics, and biopesticides. Recombinant DNA technology has served to improve the production of all of the above products. Molecular manipulations have been added to mutational techniques as a means of increasing titers and yields of microbial processes and in discovery of new drugs, but have made a major impact in creating a viable biopharmaceutical industry. This industry has made a fantastic impact in the business world, yielding biopharmaceuticals (recombinant protein drugs, vaccines, and monoclonal antibodies) having markets of many billions of dollars. It also produced a revolution in agriculture and has markedly increased the markets for microbial enzymes. Today, microbiology is a major participant in global industry and will be a major player in the new bioenergy industry, hopefully to replace petroleum within the next 50 years.