This book, first published in 1986, argues that there is a special category of medium powers in the world – such as Britain, France, India, Brazil, Japan, China and others – which have sufficient military power to do something to protect their interests but which are not a match for the superpowers. It surveys the whole range of naval warfare – equipment, operations, organisation and deployment – and discusses how each item should be tailored by the recognition of the position of the medium power. It considers alliances, a key element for medium powers, and explores how these should be handled and what use they may be expected to fulfil. The book argues that the concept of medium power, here developed thoroughly for the first time, will be extremely useful to many countries in defining their strategic role in a purposeful way.