This book attempts to address potential environmental risks posed by Bt cotton in Vietnam. It provides an excellent summary of the vast amount of data on Bt cotton since its commercialization over a decade ago. It also contains a useful overview of cotton production in Vietnam. But the book does not completely fulfil its promise to be ‘used as a technical manual to enable Vietnamese scientists to evaluate the potential environmental impacts of Bt cotton prior to commercialization’. First, with the exception of Chapter 12 on the possible development of Bt resistance in the insect pests, there is insufficient focus on the potential risks that are specific to Vietnam. Second, the book does not provide a detailed road map of how to address the potential risks in a logical, comprehensive and scientifically justified fashion. Third, the book does not take full advantage of information generated elsewhere to make informed judgments for Vietnam. For example, Chapter 5 focuses on assessing Bt cotton effects on non-target arthropods, and attempts to justify the necessity of field-testing nearly all, if not all, future hybrids despite an abundance of existing information on the gene, the plant in which it is expressed and the receiving environment. A far more efficient and rigorous assessment would be the tiered-testing approach that has been advocated by the US Environmental Protection Agency and the Western Palearctic Regional Section of the International Organization of Biological Control which relies on relevant information from previous studies to determine if additional tests are needed.