Based on the person-centered approach on one hand and developmental psychological knowledge on the other, this textbook supports the reader in reflecting on and expanding their counseling and therapeutic competence when working with adolescents. Young people grow up under very different conditions, which can provide a more or less favorable start in life. During the transition between childhood and adulthood, life seems to become completely out of balance. The prolonged transition period requires constant new adjustments. The proportion of adolescents exhibiting behavioral problems or mental disorders is steadily increasing, and with it, the demand for professional support is also rising.