Twyman is a personality in the field of spectroscopy and applied optical measurement. His spectrochemical abstracts compile the literature of spectroscopy during 1933-1937. There are fifteen pages of author references arranged alphabetically. The remaining thirty-four pages are classified into biologic material, earths, electrodes, gases, industrial materials, liquids, metals and alloys, minerals, nonmetals, oxides, precipitates, soils, apparatus, methods, general, and a list of books. Any active worker in spectroscopy has his own filing system. The value of Twyman's references lies in his careful selection of manuscripts. There are, of course, certain omissions of literature data and larger treatises on spectroscopy, but they will be noted by the modern spectroscopist. In general, the little brochure is a handy tool on the table of any scientific worker making use of spectroscopic apparatus.