The most complete and practical guidebook to Baja is The Magnificent Peninsula, by Jack Williams. Highly recommended - don't plan (or take) a trip to Baja without it!
For more details on recreation and side trips, there is The Baja Adventure Book, by Walt Peterson. If you specifically need information about side trips on unpaved roads (truly the way to see the best of Baja) get a copy of Backroad Baja, by Patti and Tom Higginbotham.
As so often, I find the Lonely Planet and Moon Travel Guides to be equally good. They are: Lonely Planet Baja California & Los Cabos by Wayne Bernhardson (a former Berkeley Geography colleague of mine), and Moon Baja: Tijuana to Cabo San Lucas, by Nikki Goth Itoi.
Maps and Atlases
The best map of Baja California by far is published by the Automobile Club of Southern California, and simply titled Baja California. It has been meticulously researched and kept up to date for over fifty years, starting back when there were precious few roads anywhere between Ensenada and La Paz.
Pretty slim pickings here - aside from a few novels that focus on the border area, and collections of hunting/fishing trip stories, I haven't found much.
One genuine piece of Baja fiction, though, is King of the Moon, by Gene Kira, about fisherman in southern Baja. Much less genuinely Mexican, but certainly entertaining, is B. Traven's The Treasure of the Sierra Madre, better known for its film version with Humphrey Bogart.
History and Biography
Presumably there are historical works about Baja in Spanish, but there is really very little in English. The inimitable Harry Crosby put together a wonderful account of The King's Highway in Baja California, unfortunately now out of print.
Graham Mackintosh's engaging account of his eccentric endeavour to walk entirely around the Baja Peninsula, Into a Desert Place, is well worth reading, either just for entertainment or to learn about Baja.
Baja is the subject of two of the all time great classics of nature writing: The Forgotten Peninsula, by Joseph Wood Krutch, and The Log from the Sea of Cortez, by John Steinbeck (and, implicitly, his pal "Doc" Ricketts). Both are excellent reading, whether you have been to Baja or not.
We are fortunate to have excellent Baja-specific field guides to both plants and geology: Roadside Geology and Biology of Baja California, by John Minch; and The Baja California Plant Field Guide, by Norman Roberts.
Given its dramatic terrain and proximity to Southern California, Baja would seem a favored setting for movies. But so far, all I have come up with is that parts of Titanic were filmed on a huge outdoor set on the coast between Tijuana and Ensenada.
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