The focal length and aspect ratio are determined from the parameters used in the equation in the book. For example, the aspect ration is (r-l)/(t-b) and the focal length (as you appear to be defining it) is n/(t-b).
Thanks Brother Bob,
I guess I need to go over it some more. It seems like, in the book, the near plane is actually replacing the view/projection plane. Is that right? I apologize if this is obvious, but I seem to stumbling on it for one reason or another.