The studies for and publication of this book were made possible through funding from IUCN, the World Bank, the Toyota Thailand Foundation and the Kobfai Publishing Project. The aim of the book is to help people with no formal botanical training to identify in the field the trees that they are likely to find in the forests and parks of northern Thailand. The 880 species covered in the book represent over 75% of the trees native to northern Thailand, including all the common forest species and many others that are easily recognized or ecologically important. A small number of introduced species have also been included that have either become naturalized or are easily mistaken for native species. The book is arranged in 6 parts. The Introduction contains sections on how to use the book, field procedures, topography, physical geography and vegetation types of northern Thailand, forest profiles, general identification keys, and identification keys for distinctive characters. Part I, The field guide, gives descriptions, habitat details, flowering and fruiting times, local names, information on similar species, and keys for the main families and genera. There are numerous line drawings and colour photographs. Part II, Additional information, gives full scientific names, synonyms, references, and details on distribution and uses (of wood or other products from each species). The appendices provide further information in the form of a glossary, a families comparison table, comparison tables for different group, a bibliography and further reading. There are indexes to local names, English names, species (inc. synonyms) and families.