back of the book
Noun
Meaning
(publishing, broadcasting) Less important or less hard-hitting material relegated to the later pages of a print publication or the later stages of a television broadcast.
Used other than figuratively or idiomatically: see back, book.
Source: en.wiktionary.orgRelated terms
Examples
I learned quickly, as I tell my graduate students now, there are no answers in the back of the book when the equipment doesn't work or the measurements look strange.
It's not as if I'm trying to write crossword puzzles to which one might find an answer at the back of the book or anything like that.