Why do some people get obsessive–compulsive disorder (OCD) and not others? Why are people unable to part with worn out or useless possessions? Is body dysmorphic disorder the archetypal obsessive–compulsive spectrum disorder? How do you manage patients who only partially respond to selective serotonin reuptake inhibitors?

These are just some of the questions answered by over 20 authorities from both sides of the Atlantic in Obsessive–Compulsive Disorder. Theory, Research and Treatment, a succinct yet broad view of OCD. The scope of the book is wide, including chapters on the phenomenology of OCD, primary obsessional slowness and OCD in children and adolescents.

The chapter introducing a cognitive–behavioural model to explain compulsive hoarding is particularly impressive. The authors use the story of Dante's Inferno to illustrate this condition. Dante's hoarders are sent to the fourth level of hell, condemned to bash each other with their hoarded stones for eternity. The authors liken this to a recent event in Massachusetts, in which a number of people died because hoarded possessions caught fire and blocked escape routes.

Danger ideation reduction therapy (DIRT) is described as ‘a viable alternative to standard interventions for compulsive washers’. It aims to eliminate patients' illness beliefs by reevaluating their perceptions of risk rather than engaging them in exposure and behavioural experiments. A randomised controlled trial of DIRT and exposure response prevention is currently underway.

Almost a third of the book is devoted to atypical presentations and subtypes of OCD. Treatment of obsessions, ruminations and covert compulsions is introduced, but I was left wanting to know more about practical interventions for successfully treating patients whose primary problem is obsessions.

Rachman's readable The Treatment of Obsessions proposes an 18-piece ‘toolkit’ for treating patients' obsessions, and also gives readers a theoretical basis for thinking about cognitive and behavioural treatment planning. He advocates encouraging patients to analyse their intrusive thoughts, their meaning and interpretation. Reducing misinterpretations, he argues, reduces obsessions. His six case vignettes give a vivid sense of the difficulties that therapists and patients face when tackling disabling obsessions. Although in the first vignette the patient responds well in just eight sessions, he describes other patients who only partially respond and he is pessimistic about the outcome for patients with a previous psychosis.

Psychiatrists should make space on their shelves for both these cogent texts. Although written independently they are remarkably compatible, Obsessive–Compulsive Disorder providing a sound introduction to OCD and The Treatment of Obsessions being an excellent practical guide.