Bipolar disorder is a common psychiatric condition that is one of the leading causes of disability worldwide. As a dynamic, recurrent, and chronic illness, it can be complex to identify and manage. In this Primer on text, leading international authors explore aspects of clinical presentation epidemiology, etiology, neurobiology, and treatment of bipolar disorder. The text provides a readable but comprehensive overview of this common illness. The book has been organized into three major sections describing different aspects of bipolar disorder: Clinical Presentation and Epidemiology; Etiology and Neurobiology; and Treatment. This organization is not intended to imply that these various components are truly distinct but rather allows readers to quickly locate specific areas of interest. Treating bipolar disorder is challenging but is ultimately rewarding because good care can make it possible for these individuals to succeed in all aspects of life.