Chapter 1 provides an overview of this title, suggesting that low intensity cognitive behavioural therapy (LI CBT) represents a revolution in the delivery of mental health services; the dawning of a new values-based paradigm, which places improving access to effective psychological treatments as the guiding principle for the endeavour. The historical underpinnings of LI CBT are traced and defined. In the remainder of the chapter, a variety of ways in which LI CBT represents a quantum shift in the way mental health services and psychological treatments are delivered is illustrated, earning it the right to be truly termed a ‘new paradigm’