Reinforcement Learning: An Introduction, Richard S. Sutton and Andrew G. Barto, 2018 (MIT Press) - The foundational textbook for reinforcement learning, providing a comprehensive explanation of Bellman optimality equations and their role in dynamic programming and optimal control.
Artificial Intelligence: A Modern Approach, Stuart Russell and Peter Norvig, 2021 (Pearson) - A comprehensive artificial intelligence textbook that includes a strong section on Markov Decision Processes and algorithms like Value Iteration, which are built upon the Bellman optimality equations.