From Viktor Frankl's "Man's Search for Meaning", developer of Logotherapy (slides)
According to Frankl, "We can discover this meaning in life in three different ways: (1) by creating a work or doing a deed; (2) by experiencing something or encountering someone; and (3) by the attitude we take toward unavoidable suffering" and that "everything can be taken from a man but one thing: the last of the human freedoms – to choose one's attitude in any given set of circumstances"
Documentary: Viktor Frankl und trotzdem Ja zum Leben sagen (DE only)