I know we already got one "Art of Star Trek" book, but the section devoted to TOS is pretty skimpy, and I'd love to see a much more extensive one for TOS, with many more pictures of props, sets, costumes, etc (although I realize most of that stuff has been sold off by now so it would probably be difficult to do).
You know they had to do concept sketches of pretty much everything before it was built or made. Is all that material lost? I think we've only seen a small portion of it.
A book like this could also be done in tandem with material about TOS' f/x suggested earlier upthread.