The section on laboratory optical work in Modern Laboratory Practice, by John Strong can be recommended. It deals with a variety of optical operations including some of those described, all treated with reference to manufacture in a laboratory workshop. The character of the book Le Travail des Verres d'Optique de Precision, by Col. Charles Deve, is well described by the author in his "avertissement". It is a resume of the technological training which is given to the apprentices of the Trade School for Optical Glass Work during their three years' course, and to the foremen and workmen who come to the Institut d'Optique. Bernard Halle's book Handbuch der Praktische Optik gives sound practical instruction for high quality optical glassworking. Amateur Telescope Making—Advanced is a collection of contributions to amateur precision optics by numerous authorities. Engineering Optics gives good descriptions of the optical systems used for engineering measurements.