Most people are simply not aware that the very first audio book was created for commercial release all the way back in the 30s. Nowadays, a good eighty years or so later, audio books on CD and in a digital downloadable format are the most popular type of audio book and the term "books on tape" is rather outdated and even considered old fashioned. With so many people enjoying their iPods and similar audio book player devices there is also great interest in finding free MP3 audio book downloads.

Even though audio books had been available for a number of years, they really gained in popularity in the late 1970s when the Sony Walkman became so popular. This small cassette tape player made it possible for people to easily take recorded material with them in a convenient way that had never before been popular. Then, about a decade later, the compact disc was introduced and suddenly the newest and best music and audio books on CD became more popular. While you can still buy an audio book on CD today, most people prefer to get their audio books in MP3 format.

There is a huge selection of free MP3 audio book titles that are available these days. However, not all MP3 audio book titles can be found as a free download. For the most part, brand new releases of popular books on CD or MP3s are still sold and are copyrighted, so they cannot be given away for free without consent from the publisher.

In some instances, an author, or their publisher, will offer a free MP3 audio book version of the work to customers who purchase the printed hardcover book. This can be a valuable incentive to the customer and also an effective advertising and marketing strategy that is particularly helpful when a brand new author is trying to gain a name and reputation.

Many times, an independent author who does not have their own publisher will build a website to promote a new book that they have written and will offer the free MP3 audio book as a bonus when the customer buys their printed book or their e-book. This can also be a good way to drive up sales or to launch a new website because people are always attracted to the potential to get something for free and most people consider an audio book download to have a lot of value, especially if it is on a topic about which they are interested.

There are a number of websites these days that have vast libraries of MP3 audio book downloads that cover just about any topic that have ever been written about. Some of these sites are membership websites and when you register as a free member or purchase a paid membership to their site, many will provide their new members with free MP3 audio book selections as a part of their membership.

Another source for many free MP3 audio book titles that you can download is the public library system. In addition, there are websites that have collected vast volumes of works that are now in the public domain and are freely available for people to download. Some of these sites request a donation to help offset their costs of providing this amazing treasury of e-books and audio books on MP3.