James West Davidson is a historian, writer, and wilderness paddler (more at jameswestdavidson.com). He received his Ph.D. in American history from Yale University and writes full time. He is also co-editor, with Michael Stoff, of New Narratives in American History, a series published by Oxford University Press, as well as the coauthor of several textbooks in American history, including one, with Mark Lytle, on how historians go about their work: After the Fact: The Art of Historical Detection. His most recent book is "A Little History of the United States," published by Yale University Press.From the author: On a river, an eddy line marks the boundary between slack water and swift. One side, you float idly in a calm haven; crossing the line, you're grabbed by the river and swept quickly downstream. As a historian, I've crossed more than one eddy line, each new current pulling in a different direction. One of my books is consumed with thinking about the end of the world; another describes several expeditions across the barrens of Labrador; yet another views the rise of segregation through the eyes of one woman. A common theme uniting these starkly different subjects is an attraction to journeys and their obsessional consequences. If you believe that the prophecies of the Bible are playing out around you in real time--and that the world's end may be drawing nigh--how does that belief affect your day-to-day social and political views? I explored that question in "The Logic of Millennial Thought: Eighteenth-Century New England." If you are a black woman born into freedom after the Civil War, and wish mainly to teach school, find a husband and enjoy a decent middle-class life, how do unfolding events in the 1880s and 1890s propel you to risk life and limb by speaking out against the rising epidemic of lynching? That's the subject of "They Say': Ida B. Wells and the Reconstruction of Race." If you launch into the wilderness of Labrador in 1903, hoping to win fame as a young journalist, how far will you court starvation in order to succeed? And if you're the widow of the man who pushed too far, where will your own compulsions lead you? "Great Heart: The History of a Labrador Adventure" retraces those life-and-death obsessions.We all begin journeys thinking we know where we're going. We seldom do. Yet the particular path of every life springs from the way in which an individual bends, breaks, or masters the larger movements of the day. As a historian, retracing such journeys provides a singular pleasure, akin to riding the unpredictable currents of a river from its turbulent headwaters to its final outwash in the sea.