Ulcerative colitis and Crohn's disease remain a major challenge within gastroenterology. Their aetiology remains unknown and provides a major intellectual challenge, although much progress is being made in understanding the influence of gene mutation on susceptibility to disease and on the course and behaviour of that disease. Diagnostic methods have improved and the advent of colonoscopy, with the ability to take multiple biopsy specimens, has not only widened our diagnostic vision but has allowed the detection of dysplasia. Surveillance colonoscopy has been introduced as a result and continues to stir up controversy. Treatment, having remained static for almost 50 years, has become enormously exciting, with many new avenues being explored. It has been informed by progress in our understanding of disease pathogenesis and, as such, is highly stimulating and provides an excellent paradigm for treating disorders of unknown aetiology. The book, the proceedings of Falk Symposium 147 on 'Colitis: Diagnosis and Therapeutic Strategies', held in Birmingham, UK, May 6'7, 2005, provides an update for any gastroenterologist, medical or surgical, with an interest in inflammatory bowel disease. Clinically important aspects of diagnosis and treatment are covered but underpinned by scientific mechanisms. It is an exciting book which looks into the future as well as informing current practice.