Which is also called
The Hitchhiker's Guide to the Galaxy.
The Big Bang Theory Season 8, Episode 8
Apparently, he's 12-down in
the TV Guide crossword puzzle.
The Big Bang Theory Season 7, Episode 19
If my father's any GUIDE,
around 50,
The Big Bang Theory Season 12, Episode 5
But when I was studying
that railway GUIDE,
The Big Bang Theory Season 10, Episode 15
...so that he could write an entry about Earth
for The Hitchhiker's Guide to the Galaxy.
The Big Bang Theory Season 8, Episode 8