The audiobook* format does have limitations:
1. Some written wordplay intended by an author (e.g., the "their/there/they're" distinction) loses its power in audio format.However, these limitations are all outweighed by the positives:
2. The success of an audiobook relies heavily on its narrator (or cast, in the case of a full-cast production). A good narrator will create specific, consistent voices for characters that match up (if not exactly, at least well enough) with how you feel the each one should sound. This is why it is a riskier proposition to listen to something on audio that you have first had the pleasure of reading, just as most books-to-movies suffer from the transition in the eyes of their fans: you've already created a mental image, or voice, that can be difficult to reconcile with the recorded version. Also, let's face it, there are some terrible narrators out there.
3. Just as a driver cannot pay 100% attention to the road while talking on a cell phone, a driver cannot pay 100% attention to a book on CD while in transit. It sometimes seems easier to become distracted when listening to a book. However, in my experience the brain is usually able to fill in the missing information with the help of current context. Plus, there's that handy "rewind" feature.
4. Sure, a book can end up missing some pages, but CDs (on which I listen to most of my audiobooks) are fragile, and coming from a multiple-use source like the library, are all the more likely to be scratched, dinged, and otherwise rendered unreadable by a media player.
1. Audiobooks make it possible for those who cannot or do not physically read, for whatever reason, to have the experience (in a variety of formats: see below). This includes people for whom English is not a first language; I've had several patrons who request items on audiobook because they can understand the spoken version more easily than the written. In addition, some people are visual learners, but some people aren't. Audiobooks create the space for a different kind of experience.[ETA: One of the best examples of some items on this pro/con list is Sherman Alexie's The Absolutely True Diary of a Part-Time Indian, which, if you read the print version, has cool little drawings that enhance the text. However, if you listen to it, you get an unabridged version performed by the author himself, which is absolutely not to be missed. Ideally one would do both.]
2. Just as a poor narrator can totally ruin an audiobook, a great narrator delivers a satisfying experience that is akin to settling in on the couch to watch a favorite movie or staying up all night to finish a book. You will realize this is happening when you don't want to leave the car because you're in the middle of "a good part."
3. Listening to a good book in the car. Instead of wondering why traffic isn't moving fast enough. With audiobooks and a longish commute, it is possible to almost double the amount of books you read. 'Nuff said.
4. Audiobooks can be an awesomely fun group activity, especially on long road trips. Yes, you could create the experience yourself by reading your favorite book aloud, but let's face it: you're not a professional actor, and after a while your voice gets hoarse and it's not as much fun anymore. Listening to books in a grouop with other people opens up a space for immediate discussion, like an instant book club.
In terms of format, audiobooks have come a long way since 1931, when the talking-book program was established. They are now available not just on cassette tape (currently being phased out at most libraries) and CD, but via MP3 players, streaming on the internet, and on Playaways.
To conclude: I heartily recommend listening to books in audio format. My advice to people who have never tried it before is to pick a book you've been interested in reading, maybe something out of your comfort zone, and listen to it instead. Ask someone who is enthusiastic about audiobooks to recommend something, or at least to recommend a good narrator. And as always, GO TO YOUR LIBRARY to get audiobooks. They are wicked expensive to buy as an individual, and (much like the majority of books) you don't end up listening to them more than once.
Side Note: This all leads to larger questions about e-books, digital technology, etc., that I may or may not address in a future post. In case anyone wants to know my position: reading a book on the computer screen, or a Kindle, or a Nook, or an iPad counts as reading, too. Even if it was never published in "book" form.
*I prefer the one-word term "audiobook" over "audio book," for some reason.