The Sorensen Therapy for Instability in Mood (STIM) is an important new psycho-educational and cognitive therapy for treating bipolar disorder (BPD). This STIM manual and client workbook offer a psychological therapy which has proven to be highly effective, inexpensive to implement, and popular with clients. It can be delivered in four 60-minute sessions by practitioners with little specialist training and results in significant improvements in the client's perceived control over mood.