An audio book is a recording of the contents of a book read aloud.

In 1933, anthropologist J.P. Harrington, drove the length of North America to record oral histories of Native American tribes on aluminum discs using a car battery-powered turntable. Audio books preserve the oral tradition of storytelling that J.P. Harrington pursued many years ago.

Audio books are usually distributed on CDs, cassette tapes, or digital formats (e.g., MP3 and Windows Media Audio).

The term "books on tape" is frequently used as a synonym for audio books, but cassette tapes are no longer the dominant media for audio books. In 2005, Cassette-tape sales made up roughly 16% of the audio book market,[2] with CDs sales accounting for 74% of the market, and downloadable audio books accounting for approximately 9%. In the United States, the most recent sales survey (performed by the Audio Publishers' Association in the summer of 2006 for the year 2005) estimated the industry to be worth 871 million US dollars. Current industry estimates hover at around two billion US dollars per year.

Most new popular titles put out by the major publishers are available in audio book format simultaneously with publication of the hardcover edition. There are approximately 25,000 current titles on cassette, CD, or downloadable format.

Unabridged audio books are word for word readings of a book, while abridged audio books have text edited out by the abridger. Audio books also come as fully dramatized versions of the printed book, sometimes calling upon a complete cast, music, and sound effects. Each spring, the Audi Awards are given to the top nominees for performance and production in several genre categories.

There are quite a few radio programs serializing books, sometimes read by the author or sometimes by an actor, most of them on the BBC.