What is the ISBN of The Exorcist?

There are actually multiple ISBNs for *The Exorcist* depending on the edition and format.

Here are a few examples:

* Original hardcover edition (1971): ISBN 0-399-10556-2

* Modern paperback edition: ISBN 0-446-67909-3

* E-book edition: ISBN 978-0-307-58954-2

To find the specific ISBN you are looking for, it's best to search online book retailers like Amazon or Barnes & Noble, using the full title and author name.