I found "Foundations of Deep Reinforcement Learning - Theory and Practice in Python" by Laura Graesser and Wah Loon Keng quite helpful in that it was somewhat like get a excellent summary course in about 6 years of RL advancements. I will say that it's quite forthcoming with the math. Anyway, I just wanted to know how they (not sure exactly who did it first, I just meant people with machines) got RL to play Atarti Pitfall. So take any recommendation I make with a grain of salt.