How to Win Friends and Influence People. - Dale Carnegie
Influence - Robert Cialdini
Books on understanding how to push through adversity
The Obstacle Is The Way - Ryan Holiday
Man's Search For Meaning - Victor Frankly
Books on process improvement
The Phoenix Project
The Four Hour Work Week - Tim Ferriss (ignore the outsourcing bit, listen to his podcast)
Books on breaking out of your thought bubble.
Outliers - Malcolm Gladwell
Ishmael - David Quinn
Books for understanding how sales works
Ultimate Sales Machine - Chet Holmes
Negotiate As If Your Life Depended on It - Chris Voss
Any of these books are great starts. If the leadership big bites you there's way more I can suggest. Most of these are a mix of classics and new stuff. I've read them all and they want have their own style and provide their own insight. The trick is to find out what parts work with how you do and incorporate them into your flow. The learning process never ends.
They succeeded because they [somehow, for one reason or another] got away with their bad traits (or what we perceive as bad trait nowadays), and they became famous because of their good traits.
I’m not sure what “questionable person” means. The Wikipedia article describes criticisms and I’m glad they are documented, but seem to come down to criticism of his philosophy by some peers.