A somewhat formal or literary term for a book, often implying a physical volume or a work of some substance. In everyday speech, 本 is more common.
He collects rare books.
この書物は18世紀に書かれた。
This book was written in the 18th century.
He authored a book on history.
I skimmed through a few books before the business trip.
That book was published during the Meiji era.