By the LakeBy: John McGahern With this magnificently assured new novel, John McGahern reminds us why he has been called the Irish Chekhov, as he guides readers into a village in rural Ireland and deftly, compassionately traces its natural rhythms and the inner lives of its people. Here are the Ruttledges, who have forsaken the glitter of London to raise sheep and cattle, gentle Jamesie Murphy, whose appetite for gossip both charms and intimidates his neighbors,