Albert Ellis was an American psychologist and psychotherapist, best known for developing Rational Emotive Behavior Therapy (REBT) in the 1950s. He emphasized the role of thoughts in influencing emotions and behaviors, advocating that irrational beliefs lead to emotional distress. His work laid the foundation for cognitive-behavioral therapy, which is widely used today. Throughout his career, Ellis authored numerous books and articles, contributing significantly to the field of psychology. He founded the Albert Ellis Institute in New York City, where he trained therapists and conducted workshops. His innovative approach has helped many individuals manage their mental health and improve their quality of life.