I just updated your lovely plugin to the latest and greatest. Now it doesn't show the right book! First, I thought it was just a variation in book cover, so I plugged in the next book in my stack to read - and it brought up a completely different book!
I am putting in the ISBN# 9780439064873 (Harry Potter Book #2). When I hit "save options", it changes the ISBN to 9781416549345. I tried entering without the 978 in front, and it changed it to another completely different ISBN, 9780785824121.
Not sure exactly what is going on, but I've had to remove the widget. Until this matter is resolved, I don't want to display books that I'm not even reading!