Broadway: The American Musical

Tonight, I watched the first two hours of "Broadway: The American Musical" on PBS. It was great to hear recordings and see film clips from the late 1920's and early 1930's. (Or were all the film clips from the early 1930's? It was hard to tell. Were any of the Ziegfeld Follies stage shows of the 1920's ever filmed?) I have also taken a look at the companion book, Broadway: The American Musical, in hopes of finding at least a reference to Louise Brooks and her time with the George White Scandals and Ziegfeld Follies. But, alas, there were none. Except, perhaps, for the image on the back of the book which depicts the Follies of 1925. Is Brooks included in that shot?