Biomass pyrolysis has been practised for centuries in the manufacture of charcoal for industry and leisure. Only in the last two decades, however, has attention focussed on a better understanding of the science and technology, with the resultant benefits of better designed and controlled processes that give high yields of liquid products. These liquids, or 'bio-oil' as it is referred to, can be used in a variety of ways: -combustion to replace conventional fuel oil in boilers, process equipment such as kilns and in gas turbines for power generation; -upgrading by hydrotreating or with zeolites to gasoline, diesel and other hydrocarbon fuels, of chemicals; --extraction and upgrading to fuel additives and chemical specialities. Any charcoal produced can also be utilised to form char- water slurries, analogous to coal-water slurries, or bioi-oil slurries which may be used as liquid fuels in many combustion applications. A group of experts was set up in the EC Energy from Biomass programme to evaluate the status and opportunities for deriving useful liquid products from biomass pyrolysis. This book is a report of their findings and conclusions. It forms an authoritative guide to the wide range of technologies employed in biomass pyrolysis, and product upgrading, utilisation and characterisation. Recommendations and conclusions are included to identify promising areas of research and development that will be of value to researchers, planners and companies throughout the world.