1. The Sudoku Murder (2007)This first book in a new series introduces mathematician and Sudoku whiz Katie McDonald. Katie, a self-professed geek who works for a hush-hush government think tank, returns to her hometown of Granville, NH, at the behest of her former mentor, P.T. Avondale. Katie is shocked to find Avondale frail and preoccupied, his beloved puzzle museum in serious disrepair and dire financial straits. Before Katie can make sense of the situation, she discovers Avondale murdered in his office—slumped over an unfinished Sudoku puzzle that may provide a clue to the killer’s identity. She tops the brash new police chief’s suspect list and decides to solve the case on her own, not only to clear her name but to save the Avondale museum from the wrecking ball.