I came across this tutorial series on Reinforcement Learning by Arthur Juliani: [WWW]
Fundamentals textbook :
Reinforcement Learning: An Introduction – By Richard S. Sutton and Andrew G. Barto
Freely available online : https://webdocs.cs.ualberta.ca/~sutton/book/the-book.html
Video Tutorial by R. Sutton.
OpenAI is an research organization for RL. They have a environment called OpenAI-Gym (Python), useful for learning RL agents.
More Resources for Quick Learning