Across the country, in the middle of busy city squares and hidden on quiet streets, there are nearly 200 statues erected in memory of Abraham Lincoln. No other American has ever been so widely commemorated. A few years ago, anticipating the bicentennial of Lincoln's birth in 2009, Jim Percoco, a history teacher with a passion for both Lincoln and public sculpture, set off to see what he might learn about some of these monuments-what they meant when...