This document discusses reinforcement learning, an approach to machine learning where an agent learns behaviors through trial and error interactions with its environment. The agent receives positive or negative feedback based on its actions, allowing it to maximize rewards. Specifically: 1) In reinforcement learning, an agent performs actions in an environment and receives feedback in the form of rewards or punishments to learn behaviors without a teacher directly telling it what to do. 2) The goal is for the agent to learn a policy to map states to actions that will maximize total rewards. It must figure out which of its past actions led to rewards through the "credit assignment problem." 3) Reinforcement learning has been applied to problems like game playing, robot control