I have heard this called one of the most important/moving/influential/inspiring books ever written, and I have to agree. Viktor Frankl survived the concentration camps, and wrote this memoir/explanation of logotherapy to reflect on the idea of survival, finding purpose, and allowing life's meaning to find you. It's hard to sum up, but this is a really good book for personal reflection and development. It's self-help, but without the feeling that the author is trying to sell you a product or develop their brand.
