Answer to Byron the Bookworm

114 holes.
Did you remember that when books are placed together as shown, page 1 of a book is next to page 100 of the book on its right.
Did you also remember that a 100 page book has only 50 leaves of paper (numbered on each side).

A hole through one leaf of paper is a hole through two numbered pages.
Looking at the books as shown, Byron started from p 42 of vol I and, traveling from left to right, made 21 holes to p 1 of vol I.
He then made 50 holes through all of vol II, and 14 holes from p 100 to p 73 of vol III.
He then turned and made 14 new holes back to p 100 of vol III, and 15 holes from p 1 to p 31 of vol II.
He didn't eat a hole through page 31 of vol II as he is still on it.
21+50+14+14+15 = 114 holes.