I've had my D 7500 for about a year, and purchased the "Dummies" manual for it, (A very good book) and used it and the factory manual to become fairly well acquainted with my D 7500, but there was always the niggling thought "There's got to be more." In the first two chapters of Busch's book, I discovered how to use the touch screen feature and interpret two menu items regarding the on-board flash, which I had tried to understand, referring to the other two books, but with little success. I had almost figured it out on my own, and Busch's manual removed any doubt. I was right!Well-written, clear, and to the point. It looks like it has about as many pages as the factory manual, which is fine with me. By the time I have finished studying it, I will have learned a lot. Worthwhile, If you want to unlock the mysteries of your D 7500, and he makes recommendations regarding equipment, which may be useful.A worthwhile purchase!