For painters and students, I have found the following to be helpful.
Most of the books I recommend are out of print but book searches such as Advanced Book Exchange can be helpful. I've also spent many a pleasant hour scouring everything from garage sales to used bookstores, sometimes with very rewarding results.

Suggested Reading

The Painter in Oil, by Daniel Parkhurst
Originally printed in 1898, this book is a treasure to me as a window into the thinking and methods of a generation of painters I greatly admire. Some of the technical advice, especially on pigments, is out of date, but the book contains much that is helpful for painters.
It is readable online at www.artrenewal.org

The Practice of Oil Painting and Drawing , by Solomon J. Solomon
Also out of print, but of undeniable value to any serious painter.

Composition of Outdoor Painting, by Edgar Payne
Available in reprint. Any time a book on painting is authored by a capable painter, it’s worth a look. This book is a great resource on one of the least understood aspects of painting today.

Frederick J. Waugh, American Marine Painter, by George Havens
Rare. Especially interesting for painters of the sea.

Pietro Annigoni, an Artist’s Life, as told to Robert Wraight
A great painter of the 20th century, I became familiar with Annigoni through my teachers, who had visited Florence and met him.

The Drawings of Rembrandt. Volumes I and II, Dover Publications
An inexpensive tour into the mind of a genius, copies of these books are possibly still lying around, overlooked, in a used bookstore near you.

The Practice & Science of Drawing,by Harold Speed

The Artist’s Handbook of Materials and Techniques, by Ralph Mayer
I refer to this whenever I run into questions about materials and the like.
It’s very dependable, and is important to have access to.