A dark moment in Irish history is explored in "The Killing of Major Dennis Mahon," by Peter Duffy. Mahon was ambushed and killed during a roadside attack in 1847, during the height of the Irish Famine. Mahon controlled land on which some 12,000 peasants struggled mightily to scratch out a meager existence. What precisely spurred Mahon's killers? Were they justified? These are some of the questions Duffy explores in a fair and balanced manner. The book also takes a close look at the trial of Mahon's killers, and how prejudices of the day and other factors played out in the courtroom. ($25.95 / 352 pages / HarperCollins)