How about a special effects book---just the efx of TOS. I know some are thinking, "well, there's not that much, so much was recycled, and had budget limitations," but i've seen magazine-length studies of the RKO King Kong numerous times, and TOS certianly had more going on in the efx department than that one film.
Over the decades, many a book or magazine covered the EFX of TOS, but have we been exposed to everything? All surviving produtction house notes, photos, unused film clips, etc.?
I would totally buy a book on the EFX.
They could start with when the plans were recieved to the building of the enterprise and the daily journals of the efx employees (if they even existed) They could cover the different tests they did and when an optical printer got jammed on a deadline.