ONE hundred and fifty million tons of “wood waste” are produced annually, most of which, it is claimed, finds no useful application. Possible methods for the utilisation of this material are its destructive distillation to give valuable products, its employment directly as a fuel, its use in paper production, or its fermentation to produce ethyl alcohol. The first application, and wood distillation generally, although forming the subject of an ancient industry, has not hitherto been taken as the sole title of an English text-book. On account of the important economic problem involved the author has much to justify his r effort, and from many points of view his book is a success. The descriptions of plant and processes for wood distillation and of stills and evaporators employed in the recovery of the distillation products are lucid, and while technical details have been considered, exactness in statement has been maintained. The Destructive Distillation of Wood. By H. M. Bunbury. Pp. xx + 320. (London: Benn Bros., Ltd., 1923.) 35s. net.