Modern organizations expect their employees to be proactive, show initiative, take responsibility for their own professional development and to be committed to high quality performance standards. They need employees who feel energetic and dedicated – i.e., who are engaged with their work. It is therefore not surprising that the past decade has witnessed a sharp rise in scientific studies on engagement. The work engagement research discussed in this book offers evidence for the incremental validity of engagement over and above traditional I/O concepts. Work engagement provides a distinct, valuable perspective on the experience of work.