X: The number ten. An unknown quantity. A mistake. A cross. A kiss. X: The shortest entry in Webster's Unabridged. 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. The test is whether she can prove her case against him before she becomes his next victim.,Provided by publisher.