I agree, Journey to Ixtlan is one of the best I've seen yet. It's the third in the series, and it basically re-states the material from the first two books but without the hallucinogenic drug aspect, which was very prevalent in the first two. He basically starts Journey by saying that he got too pulled into the hallucinogens and that it was a mistake, though it did open him up to the shaman's world.

It's an amazing read, and has a lot about lucid dreaming in it, though the only practical thing about LDing is the technique of looking at your hands in a dream to go lucid, and then shifting your attention from object to object in the dream so it doesn't destabilize as it will if you look at one thing too long. That said, while there isn't much of a practical technical value about how to achieve lucids... it's an amazing read!! And a great place to start reading Castaneda.