That was the second book on lilies that I have. As you say, very good, but has a lot of information for the more advanced.
This was my first book - 50 pages and tons of line drawings.
In my opinion, it really is the best one for someone first delving into the world of lilies, but wants to know more than just the pretty face they have. You get if free when you first join the
North American Lily Society (NALS).
If you buy things from Amazon, enter the Amazon site through the Amazon link on the right side of the NALS home page. When you do, a portion of the dollars you spend will go to NALS, without any extra cost to you. The North American Rock Garden Society (and many others) do this, and it's an easy, no cost way to help support them.
Personally, I try to limit my use of Amazon because of the unfair treatment they practice with certain authors and small publishing companies.