The second edition of the NAS handbook “Underwater Archaeology: The NAS Guide to Principles and Practice” outlines the principles and provides practical guidance for undertaking underwater archaeological work responsibly. It includes extensive advice and information on how to get involved, basic principles, essential techniques and approaches, project planning and execution, publishing and results. This new edition is fully illustrated with over 100 drawings and new colour graphics and includes additional chapters on geophysics, historical research, photography and video, monitoring and maintenance and conservation. The structure and content of the handbook is mirrored by the NAS courses in its widely acclaimed, internationally recognised training programme in nautical archaeology. Each individual component of this book was written by someone who is an expert in his/her field.