You think you know her story. You've read the Brothers Grimm, you've watched the Disney cartoons, and you cheered as these virtuous women lived happily ever after. But real princesses didn't always get happy endings. Sure, plenty were graceful and benevolent leaders, but just as many were ruthless in their quest for power--and all of them had skeletons rattling in their royal closets. Princess Stephanie von Hohenlohe was a Nazi spy. Empress Elisabeth...