This new book by Danny Burns and Stuart Worsley is based on the premise that international development interventions often fail because we assume that our world is linear and straightforward when in reality it is complex, highly dynamic and unpredictable. They challenge the dominance of logical planning models and call instead for a complexity-based understanding of how change happens. The book describes three such processes, illustrated with case studies. Published by Practical Action and also available from the IDS bookshop, price £17.95.