He obviously can’t read, so his attempt to self-improve is doomed.

Have hope. You can become someone that understands this comic.

I think @eleitl@lemm.ee gets it in their comment. The joke kind of misses because of a bad book title (maybe Larson was riffing on a popular self-help book series at the time?), but the general joke afaict is that he’s stuck in a catch-22 of not being able to improve himself with a self-help book because he would need to improve himself in order to read it.