Do you put a comma between book and the author?

You do not put a comma between a book title and the author's name in a regular sentence.

Here's an example:

* Correct: I just finished reading *Pride and Prejudice* by Jane Austen.

* Incorrect: I just finished reading *Pride and Prejudice*, by Jane Austen.

However, if you're listing the title and author in a citation, you might use a comma depending on the specific citation style.