I've been wanting a good book on all the accessories, which models they fit and which they don't. For example, many will fit the 645 Super and Pro, others will only fit one or the other. I bought a grip that came without the little adapter, so the button doesn't work. I can't find the adapter but have seen grips with it included. I didn't know when I first bought the camera (grip came from another dealer). I'd really like a good exlpaination of the Connect N system. I've figured out a lot on my own but there's still much more to learn about these cameras. It's my only camera now so I'm spending more time with it.