This classic work, originally published in 1950, was a landmark in the development of the subject of tribology. When it was first published, one reviewer wrote that it 'marks the beginning of a new epoch in the study of friction and lubrication .... The most interesting and comprehensive work on a single branch of physics I have ever read.' For the 1986 reprint David Tabor wrote a new preface, reviewing developments in the subject in the 36 years since the book first appeared. He has also added an appreciation of the life and work of F.P. Bowden, who died in 1968.