What is a pronoun for book?

There isn't a specific pronoun for "book". Pronouns usually replace nouns referring to people, places, or things.

Instead of a pronoun, you would use a noun phrase like:

* It (if the book has already been mentioned)

* This/That (if the book is nearby or at a distance)

* The book

* My book

Example:

"I finished reading the book. It was a good story."