From the bookflap:
The Flavor Bible is your guide to hundreds of ingredients along with the herbs, spices, and other seasonings that will allow you to coax the greatest possible flavor and pleasure from them. This astonishing reference distills the combined experience of dozens of America's most innovative culinarians . . .
The grading system is the authors' own; in the book the pairing grades are denoted through typography:
For this graph, I translated these grades into weights, which are represented by the widths and shades of the edges.
Graph by Marcia Gray