I have quite a few Japanese garden books, and I'd recommend this one above all others as your first; and if you only buy one, buy this one.
The range of photographs for inspiration is impressive and the accompanying sketches explain points of design theory well. The text is concise yet thorough in almost every aspect you could possibly need. There is not only an extensive plant list, but every one has a photo to show you what the plant looks like too! It's the only place I found an alternative to moss that might grow in my garden.
If you want to create your first garden and don't know where to start, buy this book. You'll probably find that it's the only one you need to get good results (you'll want more, though!). The low cost compared to the huge amount of information in it makes this the best value book on Japanese gardening - in my library at least.