On April 19, 1775, thirty-eight Americans formed two uneven lines on the wet grass of the two-acre common in of Lexington, Massachusetts. They were summoned by the rolling beat of sixteen-year-old William Diamond's brightly painted drum. The order to sound this call to arms had been given by Lexington's militia captain, John Parker.As Diamond's drum rolled, Parker's men had formed up in response to a warning from a rider Parker had sent to scout the Boston road. A British column, he said, was fifteen minutes away.This is just one of the vivid scenes New York Times bestselling author Thomas Fleming sets in First Stroke, his history of the opening days of the American Revolution, beginning with the Boston Tea Party.