I had originally read Treasure Island, and thought that was fantastic. So then I notice Kidnapped on Amazon, and realized I hadn't read that one, so I got it and was blown away.
Other reviews here explain the plot which is great, but the reading keeps you on the edge of your seat, the entire way through. It is just an amazing piece of suspense writing, and so realistic down to every detail.
I highly recommend the Whispersync audio version which was narrated by a fantastic reader. I used this when I was in the kitchen making dinner or something when I couldn't hold my Kindle Fire. The book was so irresistible, I had to go through it from beginning to end and Whispersync audio worked perfectly.
If you are a writer, I think that this book would have to go on your list of must read books to help you learn the craft of good description, simple story line, characterization and suspense. I plan to listen to it again on my next long car ride playing my Kindle through my car speakers.
As a parent, I'd make sure my teens and pre-teens were exposed to this kind of exciting literature right away. I give it a highly recommend.