Rational Emotive Behavior Therapy (REBT), developed by Albert Ellis in 1955, is a short-term psychotherapy aimed at identifying and challenging self-defeating thoughts to replace them with healthier beliefs. The ABC model is central to REBT, illustrating how activating events (A) lead to beliefs (B) that result in emotional and behavioral consequences (C). REBT is particularly effective for issues such as anxiety, depression, and phobias, emphasizing the importance of rational thinking in managing emotions and behaviors.