Here are several inspiring works that can help you become a better storyteller, writer, performer, and mapmaker. This is by no means an exhaustive list, but a collection of titles picked out by playtesters and the Dungeons & Dragons creative team. For more inspirational reading, see appendix E of the Player's Handbook.
Atlas Games. Once Upon a Time: The Storytelling Card Game.
Bernhardt, William. Creating Character: Bringing Your Story to Life.
———. Perfecting Plot: Charting the Hero’s Journey.
———. Story Structure: The Key to Successful Fiction.
Bowers, Malcolm. Gary Gygax’s Extraordinary Book of Names.
Browning, Joseph & Suzi Yee. A Magical Medieval Society: Western Europe.
Burroway, Janet. Writing Fiction.
Cleaver, Jerry. Immediate Fiction.
Cordingly, David. Under the Black Flag.
Egri, Lajos. The Art of Dramatic Writing.
Ewalt, David M. Of Dice and Men.
Gygax, Gary. Gary Gygax’s Living Fantasy and the rest of the Gygaxian Fantasy Worlds series.
———. Master of the Game.
———. Role-Playing Mastery.
Hindmarch, Will. The Bones: Us and Our Dice.
Hindmarch, Will & Jeff Tidball. Things We Think About Games.
Hirsh, Jr., E.D. The New Dictionary of Cultural Literacy.
Ingpen, Robert. The Encyclopedia of Things That Never Were.
Kaufmann, J.E. & H.W. Kaufmann. The Medieval Fortress.
King, Stephen. On Writing: A Memoir of the Craft.
Koster, Raph. A Theory of Fun for Game Design.
Laws, Robin D. Hamlet’s Hit Points.
Lee, Alan & David Day. Castles.
Macaulay, David. Castle.
Malory, Sir Thomas. Le Morte d’Arthur.
McKee, Robert. Story: Substance, Structure, Style, and the Principles of Screenwriting.
Mortimer, Ian. The Time Traveler’s Guide to Medieval England.
O’Connor, Paul Ryan, ed. Grimtooth’s Traps.
PennyPress. Variety Puzzles and Games series.
Peterson, Jon. Playing at the World.
Robbins, Ben. Microscope.
Schell, Jesse. Game Design: A Book of Lenses.
Snyder, Blake. Save the Cat.
Swift, Michael and Angus Konstam. Cities of the Renaissance World.
Truby, John. The Anatomy of Story.
TSR. Arms and Equipment Guide.
———. Campaign Sourcebook/Catacomb Guide.
———. The Castle Guide.
Walmsley, Graham. Play Unsafe: How Improvisation Can Change the Way You Roleplay.
Wilford, John Noble. The Mapmakers.
Writers Digest. The Writer’s Complete Fantasy Reference.