I've been photographing informally, or at least without training, for about 30 years now. In that time I've done a lot of portrait work, and learned a thing or two about lighting. A friend gave me this book, and it's been EXTREMELY useful in pulling together all the things I knew and showing me how they relate to each other, and filling in the gaps.
I hadn't really thought about *textbooks* for photography before -- as I said, I haven't had any formal training in the field. The books I see in bookstores are too elementary and too unfocused for me; and I don't see tham as good for a beginner starting out, either. But finding some real textbooks that go into depth about particular parts of the field is an eye-opener for me.
My photos are better for it -- especially studio portraits and the still-lifes I did for a wine book last year (Terry Garey, _The Joy of Home Winemaking_, AVON). See other photos at http://www.ddb.com/photo.