Fancy Nancy pirouettes into middle-grade territory with the launch of a mystery series that has her emulating another famous Nancy—Nancy Drew. The stylish sleuth assumes the role with élan, dressed for the job in a pink trench coat and sunglasses, carrying a rhinestone-studded magnifying glass. Initially frustrated by the lack of cases to crack (“I wish we lived someplace like River Heights,” she complains. “In River Heights, criminals are lurking around every corner”), Nancy springs into action when her teacher’s prized blue marble goes missing. Nancy shows both her trademark flair for translating (“Ooh la la! Nancy felt all tingly just saying the word ‘motive.’ It meant the reason for doing something bad”) and her penchant for humorous exaggeration. As in Nancy’s earlier picture books and I Can Read titles, her affectionate interactions with her younger sister, JoJo, and their parents ground the story. O’Connor and Glasser are as in synch as ever, and readers who have grown up with Fancy Nancy will be thrilled to follow her new career path. Ages 7–10. (Apr.)