Initially these books were only distributed on tape and that is why audio books have been synonymous with books on tape for more than two decades. However, these books are more commonly available today on CD's and digital formats, such as MP3 and Windows Media Audio. It is also understandable that as technology develops these books? distribution also develops. Today you may also buy audio books online in iTunes or DVD format. For instance, a recent study shows that tape sales represented only about 16% on the market, while the CDs sales represented approximately 74%. Also, the digital books available on the Internet represented up to 9% of the sales. It was also shown that on the United States market only, the entire audio books industry was worth about 870 million dollars in 2005 and today it is believed that the estimation escalated up to two billion US dollars a year.

The great thing about this industry is that it offers a wide variety of popular titles that are being offered by the major publishers simultaneously with the actual printed publication. You can find up to 25 thousand titles on tape, CD and digital format. These books are also differentiated in two categories, such as unabridged and abridged depending if they are word for word readings of a book or, respectively if they present an edited version of the original book. These books are also fully dramatized versions of the work itself and they often call upon cast, soundtrack and sound effects. Also, each spring there are the Audio Awards that are given to those nominated as the best as far as performance and production are concerned. In order to buy audio books online you only need to access the sites offering such services and purchase your favorite titles.

The development of technology and the huge popularity of portable player devices like the iPod have also made these books more available to the public and much easier to access for portable listening. Thus, there was a quite a huge boom that resulted in the creation of several projects that provide free audio books by taking the works from the public domain and looking for volunteers to read them.

The use of audio books is not limited just to entertainment as they are more and more used by the educational system in order to teach children how to read and to increase their reading comprehension. Students learning foreign languages also find these books very useful as they offer them different aspects of pronunciation and accents. Higher education students are also known to buy audio books online, especially self help books that help them for a variety of subjects ranging from public speaking to learning meditation. The audio books are great for multitask activities or for learning while doing some other house activities like laundry or indoors exercising. Such books are also quite popular when driving and as a relaxing way of falling asleep.

Another important use of the audio books is for the blind people. There are a lot of audio libraries that offer free services to he visually impaired people in order to ensure their easy access to literature of all kinds. Most schools for the visually challenged are taking advantage of these opportunities in order to make it easier for the students to assimilate more information.

It is important to note that about 40 percent of the audio books consumption takes place by means of public libraries, while the remaining 60 percent is distributed through retail book stores. Also, the download programs offering audio libraries online are experiencing a very rapid growth mostly because they offer cheap or even free services. It has been shown that all these efforts are quite appreciated by the public and that even the illiterate people are making efforts to increase their literacy levels by listening to audio books.