Painting Expressive Pastel Portraits by Paul Leveille (1998, Hardcover)

Unlike so many of the other books and dvds I have bought, this really teaches you "how to". Many of the others - and I have bought dozens and dozens - are not at all practical but rather an artist's thoughts on a particular picture, or a hackneyed reiteration of the same old rules. You know: place the eyes half way down the head, except when they're not. This book actually shows you close-up, step-by-step, color-by-color, how to paint a portrait with pastels. Maybe someday I won't need so much detailed direction, but, hey, when that time comes I'll gladly sell the book to some one who can really use it!
Definitely worth the money and the time.