Viktor Frankl survived Auschwitz. This book, written in nine days immediately after his liberation, describes the psychological stages of concentration camp existence and outlines his therapeutic philosophy: logotherapy, the idea that finding meaning is the primary human drive. The first half is memoir, almost unbearably vivid in its documentation of horror. The second half is theory, arguing that even in the worst suffering, we retain the freedom to choose our attitude. Millions have read it. It remains one of the most powerful arguments for the resilience of the human spirit.