Existential therapy is a philosophical approach aimed at helping individuals find meaning in life and cope with existential angst rather than diagnosing illness. It emphasizes personal responsibility, freedom to make choices, and understanding the human condition's inherent dilemmas such as isolation, meaninglessness, and the awareness of death. Key figures like Viktor Frankl and Irvin Yalom have contributed to its development by focusing on the importance of meaning, identity, and confronting existential anxiety.