Far from being servants or decorative accessories in court, ladies-in-waiting competed for real positions of power--and many succeeded in their goals, sometimes betraying their queens in the process. A few even became royal mistresses, such as the rapacious Lady Castlemaine who amassed a fortune and flaunted her hold over King Charles I. Drawing on a wide variety of primary sources, including the diaries of such shrewd onlookers as Lady Cowper and...