"The American experiment rests on three ideas--"these truths," Jefferson called them--political equality, natural rights, and the sovereignty of the people. And it rests, too, "on a dedication to inquiry, fearless and unflinching," writes Jill Lepore in a groundbreaking investigation into the American past that places truth itself at the center of the nation's history. In riveting prose, These truths tells the story of America, beginning in 1492,...