ARE YOU READY FOR THE LEADERSHIP MOMENT?Merck's ROY VAGELOS commits millions of dollars to develop a drug needed only by people who can't afford it -- EUGENE KRANZ struggles to bring the Apollo 13 astronauts home after an explosion rips through their spacecraft -- ARLENE BLUM organizes the first women's ascent of one of the world's most dangerous mountains -- JOSHUA LAWRENCE CHAMBERLAIN leads his tattered troops into a pivotal Civil War battle at Little Round Top -- JOHN GUTFREUND loses Salomon Brothers when his inattention to a trading scandal almost topples the Wall Street giant -- CLIFTON WHARTON restructures a $50 billion pension system direly out of touch with its customers -- ALFREDO CRISTIANI transforms El Salvador's decade-long civil war into a negotiated settlement -- NANCY BARRY leads Women's World Banking in the fight against Third World poverty -- WAGNER DODGE faces the decision of a lifetime as a fast-moving forest fire overtakes his firefighting crew