Has anybody kept actuarial statistics on those faculty parties? They must be more dangerous than skydiving. This one, president Avery Mitchell's annual Christmas bash for the staff of Enfield College, leaves logorrheic hotshot Randy Astin-Berger, who's been putting the moves on newcomer Karen Pelletier, welcomely silenced and immobilized by a strategically applied necktie. (Bonnie Weimer, a student whose whining is stilled by similar means soon after, proves that academic life itself is dangerous, since the more you talk the more likely you are to get killed.) It's not easy for Karen to tear herself away from her romantic preoccupations--the husband she left back in New York to take her teaching job, her fascination with President Mitchell's cute buns, her love/hate mating dance with investigating homicide cop Lt. C. Piotrowski--and her determination to protect brilliant, suicidal student Sophia Warzek from her family demons. Egged on by Piotrowski, though, she gradually focuses on the mysterious letter Randy bragged about discovering. What 19th- century secret could he have unearthed that pushed one of his colleagues to murder? Emily Dickinson scholar Dobson's first novel has an appealing heroine, a nifty payoff, and a beguiling way with the extracurricular entanglements of her teaching stiffs. But suspicion is distributed more generously than are clues to the hard-to-believe killer.