Browse or search their inventory of over 20,000 titles in all categories to find the audio books you’d like to hear. Whenever you see a title of interest, click “Add to Shelf” (while logged in). The audiobook will automatically be added to the bottom of your Audio Book CD Rental Shelf. At your leisure, edit your list to make sure the books you most want to hear are at the top of your Rental Shelf. Audio Books are automatically shipped in order of availability and priority. When you're finished with a selection, just pop it back in the postage paid box and drop it into the mail. As soon as they receive your returned CD's, they'll ship your next book. It's just that simple!