Reinforcement Learning: An Introduction, Richard S. Sutton and Andrew G. Barto, 2018 (The MIT Press) - A standard textbook for reinforcement learning, with a chapter on Monte Carlo methods for value estimation and policy improvement.
CS234: Reinforcement Learning (Course Materials), Emma Brunskill, 2025 (Stanford University) - Stanford's course on reinforcement learning, offering lecture notes and video explanations of Monte Carlo methods.