Bipolar disorder has only recently been studied from a psychological perspective. There is now increasing evidence for the importance of cognitive behavioural therapy in improving functioning and reducing risk of relapse. This chapter briefly describes the rationale for a psychological approach to bipolar disorder before introducing a clinical heuristic as a context within which to appreciate the clinical examples and case formulations that follow. Key features of the assessment and therapy process with bipolar clients will be described. Targets for therapy include the stabilisation of routines and helping clients to deal more adaptively with mood fluctuations. Potential pitfalls in therapy are noted and possible solutions identified.