This is an index of model numbers of various electronics and what Photofacts book you would find their schematics in. This is the 1981 index. The front cover has been written on, and has some scratches and fading. The back cover is torn, and a square piece has been cut from it. The pages are yellowed, but they are all there and are not torn. I did see some lines that are either darker yellowing or stains on one of the advertisement pages.