Well if you've read Frankl then I think you should read Primo Levi. The Drowned and The Saved and also If This Is A Man. One could say he came to less easily swallowed conclusions, but I think it is essential reading.
For me personally however I think Dostoyevsky's Crime and Punishment more or less informed my world-view from a very young age and continues to do so.
For me personally however I think Dostoyevsky's Crime and Punishment more or less informed my world-view from a very young age and continues to do so.