An Updated Introduction to Reinforcement Learning

A while back I wrote a blog on understanding the fundamentals of RL. I’ve spent the past couple weeks reading through Kevin Murphy’s Reinforcement Learning textbook and Sutton and Barto to review some of my fundamentals. This blog contains some notes to cover topics I haven’t yet talked about in my first attempt at explaining RL! What is Reinforcement Learning? Reinforcement Learning is all about the idea of interacting with your environment to learn good behaviors. Given the full state $s_t$, observation $o_t$, some policy $\pi$, action $a_t = \pi(o_t)$, and reward $r_t$, the goal of an agent is to maximize the sum of its expected rewards: ...

October 6, 2025 · Reading Time: 44 min