Two basic approaches to engagement are contrasted. Work engagement relates to an individual's psychological state of mind while at work. The problems with this and its limited relevance to HRM are considered: its concern with a minority of employees, the way non-engaged staff are portrayed, the airbrushing out of conflict and the pernicious use of positive psychology. Employee or behavioural engagement is more relevant to HRM and employment relations but suffers from a lack of definition and a failure to specify the components that are associated with higher levels of employee engagement. It is usually a-contextual and lacks the subtlety of earlier work on HR and performance, while covering the same ground. Problems remain with research seeking to show the connections with financial performance. Boiling engagement measures down to one score is particularly worrying. The management of employee engagement in the UK National Health Service illustrates that properly constructed studies of employee engagement can inform policies and practices to improve work relations, employee well-being and aspects of performance.