You would think that with this new Internet fad there would be no place for paper rock climbing guides. Fail! There are at least three good reasons why paper guides are superior. First, they're portable. Second and third, have you ever tried to wipe your ass or start a fire with a web page? No can do, amigo!
Joshua Tree: A Color Guide to the 2600 Best Rock Climbs & Boulder Problems by Robert Miramontes crushes the sweaty-palms test. I learned to climb in J-tree with Vertical Adventures, and reading Miramontes' guide I realized it's been far too long since I've been.
This guide is well thought out, with gorgeous color photography, clear route descriptions and helpful symbology. One thing we really liked was the use of color to differentiate between sport, trad, toprope, boulder and aid climbs, and there are graded lists of each type of climbing in the back of the book. The intro has tons of useful beta on the park and logistics in the area, some cool hikes, and there are "best of" lists for different kinds of climbs, e.g. cracks, faces, etc. The only quibble is with the maps, which are based on satellite photos; they'd be more clear if they were simple line drawings, but don't let that distract you: this is the best climbing guide out there right now for Josh.