X: The number ten. An unknown quantity. A mistake. A cross. A kiss. X: The shortest entry in Webster's Unabridged Dictionary. Derived from Greek and Latin and commonly found in science, medicine, and religion. The most graphically dramatic letter. Notoriously tricky to pronounce: think xylophone. X: The twenty-fourth letter in the English alphabet. Kinsey Millhone identifies a remorseless serial killer who leaves no trace of his crimes....

It's April 1988, a month before Kinsey Millhone's thirty-eighth birthday, and she's alone in her office catching up on paperwork when a young man arrives unannounced.  Michael Sutton is twenty-seven, an unemployed college dropout. More than two decades ago, a four-year-old girl disappeared, and a recent newspaper story about her kidnapping has triggered a flood of memories. Sutton now believes he stumbled on her lonely burial and could identify the...

Of #1 New York Times-bestselling author Sue Grafton, NPR's Maureen Corrigan said, 'Makes me wish there were more than 26 letters.' With only one letter left, Grafton's many devoted readers will share that sentiment. The darkest and most disturbing case report from the files of Kinsey Millhone, Y is for Yesterday begins in 1979, when four teenage boys from an elite private school sexually assault a fourteen-year-old classmate--and film the attack....