This is the first published section of a projected reference work on enzyme research. When completed it will be about 3,500 pages long and will cover the chemistry and preparation of substrates, the methods of following enzyme activity, the detailed description of enzymes and the applications, industrial and clinical, of enzyme chemistry. The present section deals with the preparation, properties and mode of use of the following classes of substrates: the glycerides, acetylcholine, the tannins, chlorophyll, phosphoric esters, phosphatides, sulfuric acid esters, hexoses and glycosides. The treatment is detailed, thorough and systematic. If the work as a whole keeps to the standard set by the present section, the handbook will be indispensable to workers in the field of enzyme chemistry. The American contributors will include R. S. Anderson, M. L. Anson, E. N. Harvey, Moses Kunitz, J. H. Northrop and J. B. Sumner.