When I was married, my ex-Uncle-in-law worked as a finance manager for a Chrysler dealership. I asked him once about trade ins, since it was his job to inspect them. He said he looks at them, drives around the block and then checks a book... it was Kelly, but it was called a Black Book or something. He said it's what all the dealers he knew of used.

All I know is the prices in it were much less than a typical Blue Book.