Depression, often referred to as the ""common cold of psychopathology,"" is among the most prevalent psychiatric conditions, yet it remains challenging to understand and treat. Depression 101 provides a reader-friendly overview of unipolar and bilpolar depression and provides the most current and intriguing scientific knowledge on this topic. Unique in its transdisciplinary and lifespan approaches to depression, the text explicitly integrates models of depression across childhood, adolescence, and adulthood. Depression 101 establishes an organisational framework for understanding the multiple pathways that can lead to depression. It describes the fundamental distinctions between unipolar and bipolar disorders, and provides a model for understanding of mood disorders on a continuum of severity. The text illuminates how such major psychology disciplines as clinical, developmental, evolutionary, personality, and behavioural neuroscience shed light on the causes, risk factors, and treatment options for the full spectrum of depressive disorders. Cultural and gender as variables are examined as is depression across the lifespan. Additionally the text clarifies common misconceptions about depression and mood disorders, and considers how the recently-released DSM-5 affects diagnostic practice.