For questions related to the book "Reinforcement Learning: An Introduction" (by Andrew Barto and Richard S. Sutton).
"Reinforcement Learning: An Introduction" (by Andrew Barto and Richard S. Sutton) is often considered or cited as the most comprehensive introductory manual to the field of RL, by two of the greatest contributors to the field.
Two editions have been published so far. The first edition was published in 1998 and the second in 2018. You can find some material related to this book (including some drafts) at the following URL: http://incompleteideas.net/book/.