Peter Warr is Emeritus Professor of Psychology at the University of Sheffield, UK. He was previously Director of the MRC/ESRC Social and Applied Psychology Unit at that university, and has published more than 230 articles and 30 books across several areas of psychology. He is a Fellow of the International Association of Applied Psychology and has been awarded Honorary Fellowship of the British Psychological Society; that society has also presented him with its two awards for outstanding contributions to psychological knowledge. His current research concerns different forms of happiness and the links between those and behaviour.