1 Taxonomy and Phylogeny.- 2 Introduction to the Physiology and Biochemistry of the Genus Clostridium.- 3 Genetics of Clostridium.- 4 Solvent Production.- 5 Acetogenic and Acid-Producing Clostridia.- 6 Bioconversions.- 7 Clostridial Enzymes.- 8 Toxigenic Clostridia.