Odd question for this subforum...
I'm no one important, but I'm on the internet so here's my opinion:
Saxon Tales are pretty good. Lots of cowards shitting themselves and groin stabbing in the shield wall and beard growing and drinking and revenge.
The most important literature imo for promoting an attitude conducive to becoming stronger is definitely Conan. There are three books which compile all the original, unsullied works by Robert E. Howard. The Coming of Conan the Cimmerian, The Bloody Crown of Conan, and The Conquering Sword of Conan published by Del Rey Books. The short stories are compiled in the order in which they were written. The themes of primality, straight-forwardness, aggression, confidence, and simplicity translate well to lifting.