Richard Kilty of Britain celebrates after winning the men's 60 metres final during the European Indoor Championships in Prague March 8, 2015. REUTERS/David W Cerny (CZECH REPUBLIC - Tags: SPORT ATHLETICS)

Boxing is a sport more often associated with brute violence than with aesthetics. But photographer Howard Schatz has turned thuggish fighters into the subjects of extraordinary portraits showing the beautiful side of pugilism. The stunning pictures, collected in a new book, took six years to capture as Mr Schatz sought to investigate every aspect of the controversial sport.