Five ways of using the word book as a noun?

1. The noun 'book' as the subject of a sentence:

• The book is due back at the library today.

2. The noun 'book' as the subject of a clause:

• I did what the book said but it didn't work.

3. The noun 'book' as direct object of a verb:

• I saw the book at a discount, so I bought it.

4. The noun 'book' as the object of a preposition:

• I got a lot of good ideas from the book.

5. The noun 'book' as a subject complement:

• The gift was a book of classic poetry.