Picked this one up for a recent trip to Joshua Tree National Park.
The thing about guidebooks is that we all want something different from our trips, so it's hard to get one book that fits everyone's needs. This is a really good introduction to the park, with interesting coverage of the flora, fauna, and history, all of which make for good reading before you get there. It didn't cover as much of the trails as I wanted, but as mentioned above, you can't please everyone with a guide book, especially to a national park. The text is clear and concise, and this is certainly worth checking out of your library if you plan to visit JTNP. And you should - it's an amazing place.