Blue Book

What Does Blue Book Mean?
A guidebook that compiles and quotes prices for new and used automobiles and other vehicles of all makes, models and types. Formally known as the Kelley Blue Book, it was originally only available to those in the automotive industry, but both a consumer edition and an online edition was made available in the 1990s for the general public.

Investopedia explains Blue Book
The blue book has become the premier appraisal guide for vehicle price quotes in North America. Auto insurance companies frequently use the blue book as a benchmark for assessing the market value of a car that has been involved in a collision in order to determine whether it's worthwhile to fix the car or whether it should be written off as a total loss.