The original Advanced Dungeons & Dragons Players Handbook, known these days as the AD&D 1e PHB, is now available as an officially licensed digital file. The watermarked, searchable PDF is available from Dungeons & Dragons Classics or DriveThruRPG.com. Regularly priced at $34.99, it's on sale now for $9.99.
The PHB was first published in June 1978 and not widely distributed until several months later at GenCon XI. This edition's product page is accompanied by a thorough commentary by product historian Shannon Appelcline, author of the Designers & Dragons series.
As Appelcline points out, this is not the very first Dungeons & Dragons product to be published, but it is the first of what we would think of today as core sourcebooks.
The D&D game began with the OD&D box (1974), which was expanded with four supplements (1975-1976) and additional articles in The Strategic Review (1975-1976)," Appelcline said. "However, by the time that Supplement III: Eldritch Wizardry (1976) was published, TSR had already decided that the system — which now spanned a half dozen books and several newsletters — needed to be unified and cleaned up.
The AD&D 1e Players Handbook is very different from its later incarnations. From AD&D 2e onward, the Player's Handbook has been the main rulebook for the D&D game, but in AD&D 1e it only contained the most crucial rules needed by the players. That means that it explains abilities, races, classes, spells, and psionics, plus a few other bobs and bits.
What's astonishing is what's not in this book. For example, you won't find rules about how to actually roll your abilities! The Dungeon Masters Guide (1979) has that! Similarly, there are no rules for combat or even saving throws! Instead the player only got summaries of what the rules systems were like — not the actual systems!
Though this might seem bizarre today, the original Players Handbook was from a different age; players were kept in the dark about the rules of the game, and the game master was the ultimate arbiter of all the game's mechanics.
Appelcline's work here alone is worth a read, as he goes into not only the historicity of the book as an artifact — including information on the art found on the cover — but also dips into the various misunderstandings and controversies that surround AD&D to this day.