Behavioral activation is a therapeutic technique that reduces apathy and lack of interest as particularly distressing symptoms. This approach is indicated for various disorders, such as depression or social phobia. The author team demonstrates the diverse applications of the technique and provides practical examples. Possible mistakes and pitfalls are illustrated clearly. Exam questions support knowledge assessment. Additionally, instructional videos complement the offering. Behavioral activation is a classic behavioral therapy technique: it reduces apathy and lack of interest as particularly distressing symptoms, which often constitutes the necessary prerequisite for successful therapy. Therefore, behavioral activation is not only an important step but often the first step in treatment.