Book excerpt: Overcoming app now available via iTunes and the Google Play Store. Depression is one of the most common mental health problems and affects 121 million people at any time. It is recognised by the World Health Organisation as one of the Top 10 most disabling health conditions. Behavioural Activation, a therapy developed from CBT, is an effective new technique in managing depression and ideally suited to self-help. By analysing, challenging and changing behaviours such as avoidance, ruminating and excessive worrying, the sufferer can gradually reinforce their positive experiences and decrease the behaviour which reinforces their depression. Includes worksheets and practical problem-solving techniques. Step-by-step approach to analysing and changing behaviours. Includes an explanation of depression and associated behaviours and case studies. Written by leading clinicians in the field.