This fully revised and updated second edition provides worldwide coverage of an increasing variety of towing vessels, outlines the development of ever more complex propulsion systems and explains how tugs are operated in their various roles. A particular theme is today's fierce competition among tug operators, which has resulted in manpower cuts and the emergence of very small tugs with unprecedented power, capable of carrying out the work of vessels twice the size. "The Tug Book" will be of interest not only to marine enthusiasts but also to the towage industry and its employees.