I guess most people want to know more about Freddie. I certainly do. He had an air of intrique about him which Brian and Roger don't have. They're always in the media gabbering on about Queen these days to the point where I don't listen anymore. Moreoever, Roger and Brian can't even sell solo albums, so the general public isn't going to be interested in reading about them, are they? The authors want the books to sell, so they concentrate on Freddie. That's just my two cents on the matter.