Viktor Emil Frankl M.D., Ph.D., was an Austrian neurologist and psychiatrist as well as a Holocaust survivor. Frankl was the founder of logotherapy, which is a form of Existential Analysis, the "Third Viennese School" of psychotherapy.
His book Man's Search for Meaning (first published under a different title in 1959: From Death-Camp to Existentialism. Originally published in 1946 as Ein Psycholog erlebt das Konzentrationslager) chronicles his experiences as a concentration camp inmate and describes his psychotherapeutic method of finding meaning in all forms of existence, even the most sordid ones, and thus a reason to continue living. He was one of the key figures in existential therapy.
Excerpted from Wikipedia.