'Trease and Evans' is an encyclopedic reference work on pharmacognosy - the study of those natural substances, principally plants, that find a use in medicine. Its popularity and longevity stem from the book's balance between classical (crude and powdered drugs' characterization and examination) and modern (phytochemistry and pharmacology) aspects of this branch of science, as well as the editor's recognition in recent years of the growing importance of complementary medicines, including herbal, homeopathic and aromatherapy. No other book provides such a wealth of detail. A reservoir of knowledge in a field where there is a resurgence of interest - plants as a source of drugs are of growing interest both in complementary medicine fields and in the pharmaceutical industry in their search for new 'lead compounds'. Dr Evans has been associated with the book for over 20 years and is a recognised authority in all parts of the world where pharmacognosy is studied, his knowledge and grasp of the subject matter is unique. Meticulously referenced and kept up to date by the editor, new contributors brought in to cover new areas. New chapter on 'Neuroceuticals'. Addition of many new compounds recently added to British Pharmacopoeia as a result of European harmonisation. Considers development in legal control and standardisation of plant materials previously regarded as 'herbal medicines'. More on the study of safety and efficacy of Chinese and Asian drugs. Quality control issues updated in line with latest guidelines (BP 2007).