A century after Albert Einstein began postulating his "Big Idea" about time, space, and gravity, a new biography examines the scientist whose public idolization was surpassed only by his legitimacy as one of humanity’s greatest thinkers. Walter Isaacson, the author of excellent profiles of Benjamin Franklin and Henry Kissinger, utilizes a trove of material from recently opened Einstein archives to offer a probing look at a provocatively freethinking individual.