I've been using books on tape for years. At first it was to try & keep the children amused but having found it made the journey seem shorter I often use them on longer journeys . I found it more effective than music tapes which either either soothe so I start feeling tired or stimulate & I find myself speeding, or radio stations which if you are going any distance keep jumping or being interrupted by vehicles with inadequate suppression systems so just as you are getting interested you lose the signal.

On the subject of recommended authors I'm amazed that no one has yet mentioned Terry Pratchett. Most of his books are on tape & CD. The ones I have are read by Tony Robinson who has the most wonderfully expressive voice. You drive along laughing.

For children Terry Deary's Horrible histories I found very good. For the duration of the tape peace reigns in the back of the car.