In this study William Lyons presents a sustained and coherent theory of the emotions, and one which draws extensively on the work of psychologists and physiologists in the area. Dr Lyons starts by giving a thorough and critical survey of other principal theories, before setting out his own 'causal-evaluative' account. In addition to giving an analysis of the nature of emotion - in which, Dr Lyon argues, evaluative attitudes play a crucial part - his theory throws light on the motivating role of emotions in our lives, our attitudes towards our emotions and our responsibility for them.