I don't feel quite qualified to comment on his style, and even if I were, I doubt I could say something that hasn't been said about him before. All I can say is that this is a beautiful book, with a beautiful selection of his horse paitings. Also a nice alternative for those of us who like to look at his paintings but don't necessarily want to have prints of them on their walls. (prints, because if you can afford originals, you are probably not hanging around here reading my review of this book).
Anyway, if you like Franz Marc and/or if you like horses, try to get yourself a copy of this book. It's pretty and worth its money.
One of my favorite painters, Franz Marc gives life and interest to animals, especially horses. A Bavarian, he was one of the founding members of the Blaue Reiter group. Unfortunately World War I cut his life short. I just feel joyful and playful when I see his pictures.