Existential Psychotherapy is a nonfiction book by the American existential psychiatrist and author Irvin D. Yalom. In this book, the author offers a brief and pragmatic introduction, addressed to clinical practitioners, to European existential philosophy, as well as to existential approaches to psychotherapy. He presents his four ultimate concerns of life—death, freedom, isolation, and meaninglessness—and discusses developmental changes, psychopathology and psychotherapeutic strategies with regard to these four concerns.