Reinforcement Learning (RL) is a machine learning paradigm where agents learn to make decisions through interaction with environments, receiving rewards or penalties. Key concepts include rewards, policies, and value functions essential for guiding the agent's behavior. Q-learning and deep Q-networks represent significant advancements in RL, enabling effective learning in complex tasks like robotics and gaming. Mastery of RL principles facilitates the development of autonomous systems that improve decision-making through experience.