Bipolar depression is now known to exist as a spectrum of disorders rather than a single disease entity. Bipolar II Disorder exists on this spectrum as a condition where the depressive episodes are as severe as in Bipolar I Disorder, but where the mood elevation states are not as extreme. This unexpected combination can lead to a failure to detect a condition thought to affect up to 6% of the population. This book reviews, for the first time, our knowledge of this debilitating disorder, covering its history, classification and neurobiology. In a unique section, fourteen internationally recognized experts debate management strategies, building to some consensus, and resulting in treatment guidelines where no such advice currently exists. It should be read by all health professionals managing mood disorders and will be informative to those wishing to learn more about the condition.