Biomass has in recent years been considered as a raw material for the production of fuels and chemicals. This work discusses the reasons for the increased interest in mainly lignocellulosic biomass. Gasification, pyrolysis, and depolymerization by hydrolysis are analyzed as key biomass technology. We also discuss which of the sugars obtained via depolymerization by hydrolysis can be processed into fuel or key intermediates of the chemical industry. Lignocellulosic biomass contains such extractants as fatty acids and terpenes, and we therefore describe the catalytic reactions of these substances for the synthesis of fuels and chemicals. Some typical reactions of biomass processing (oxidation, hydrogenation, cracking, etc.) are conceptually close to the process widely known in the refining and chemical industries. There are, however, other considerations due to, e.g.; the large number of functional (hydroxyl and other) groups, and the processing of biomass components therefore requires dehydration, aldol condensation, ketonization, decarboxylation, etc. We cover the fundamentals of the approaches to selecting catalysts for these reactions. © 2011 Pleiades Publishing, Ltd.