A normative review of the literature describing the products, mechanisms, and rates of lignin and whole biomass pyrolysis is presented. The role of a complex sequence of competing solid-and vapor-phase pyrolysis pathways is elucidated. 175 K. W. Böer et al. (eds.), Advances in Solar Energy © Plenum Press, New York 19854.3.2.1 Products. At low pressure, anhydrosugars distill when heated to temperatures above 200°C and can be quantitatively recovered. 94 -99 However,levoglucosenone is known to polymerize in the liquid phase even at low temperatures,lOO and many anhydrosugars undergo vapor phase dehydration reactions in the presence of acid catalysts. 95 . 97 ,lOl,l02 In addition to distillation,103,l04 monosaccharides also polymerize to high molecular weight glucans which undergo subsequent fragmentation reactions, resulting in the formation of a wide variety of furans, ketones, aldehydes, and acids. l05 ,l06 Heyns and his coworkers l05 ,l06 observed the same degradation products from sixteen mono-, di-, oligo-, and polysaccharides. This caused * In Part 1 of this Review, concern was expressed over the apparent use of a (mis)identity A2 -B2=? (A -B)2 by Lewin and Basch 61 . Lewin and Basch have independently checked their work and report that their analysis did not involve the use of the (mis)identity given above. 180 CHzOH ;:::= ,t°'-O