In college I owned a Nikon El. Recently, 20+ years later, I have been buying used Leica equipment and was hoping that this book would teach me something new but it has not. The book is probably good for the absolute beginner who might rate it a '4' but offers little to even the moderately experienced. Lacks pictures of the most important lens problems (pg 56) like fungus and de-cemented elements (which is hard to see). Matter of factly says that de-cementing can be fixed by lens technicians by cleaning and re-gluing but in my experience they sure don't want to do it and if you can talk them into it they want an incredible price so why is this problem not noted by the book? Overall the advice is very general. Discusses use of a beat up a old camera (pg 31) as acceptable, though in my experience, even a new camera that had shutter problems would jam at the worst times missing the shot so I should have immediately replaced it. This sort of book should really be written by a camera repair technician wanting to help out used camera buyers.