good book

NOUN
9 LETTERS · STARTS WITH G

good book is a valid 9-letter word worth 16 points in Scrabble and 18 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
G2O1O1D2B3O1O1K5
2 + 1 + 1 + 2 + 0 + 3 + 1 + 1 + 5 =16 PTS
DOUBLE WORD → 32TRIPLE WORD → 48
MEANING

What does good book mean?