There are two types of books: non-fiction and fiction.
A book is a medium for recording information in the form of writing or images, typically composed of many pages (made of papyrus, parchment, vellum, or paper) bound together and protected by a cover.
There are around 130 million published books. The most sold book is the Bible. If you read 20 minutes a day, you would have read 1.8 million words in a year.