Book reading was revolutionized when J.P. Harrington decided to record the history of Native Americans back in 1933. Because the Native American history was mostly spoken, not written, he decided that it would be best to record their history so that it could be repeated the way they had planned it to be. Back then he used a turntable that was powered by a car battery. Now, an audio book publisher has many more options available to them. Audio books are released in almost any format available, from tapes to CDs and even to digital, so they need to try to release the book in the format that they know their listeners will most likely purchase.
It used to be that you could only get audio books in tape format. This is back when everybody had a walkman and you could spend hours winding up tape that mysteriously came out of your cassette. Then CDs became popular, so audio book publishers were able to put the books onto a CD for a wider population of people. CDs became even more popular once CD players started appearing in every car sold.
There are book publishers that publish their books in audio format themselves, while others hire other audio companies to release the audio books for them.
Now, audio books are available to buy in digital format, such as an MP3. Publishers can choose the book that they think people will want to hear, like popular novels from Stephen King or J.D. Robb, and can have an actor read it. Because audio is mainly recorded in digital format, it is a simple process to transfer the digital recording directly into a digital format. People can then download the books that they want to listen to directly online from an audio book retailer. This process has made audio books much more available to the general public.
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