Clash of Extremes: The Economic Origins of the Civil War presents a new interpretation of the sectional conflict. A one word summary of its argument is "economics." It stands apart from the prevailing viewpoint, which sets forth "slavery" as the cause of the war. Somewhat more fully, the argument is: more than any other concern the evolution of the Northern and Southern economies explains the sectional clash. The story the book tells begins in the 1820s and continues through the war and the triumph of a business-oriented Republican Party in the 1880s.   Another good summary comes from the Civil War historian William Barney. He states: "In lively and engaging prose, Egnal has succeeded in bringing back economics as a core factor in the coming of the Civil War. Readers are in for a delightful surprise as they explore his engaging analysis of how diverging economies produced conditions that led to secession."     Early in the writing of Clash of Extremes, I realized that the creation of the book was as much about a process as a product. The comments of the scholars I thank in my Acknowledgments led me to rework the text time and again. Arguments changed, chapters were recast, and sometimes dramatically so. This website emphasizes that the process of revising and rethinking does not - or should not - end with the publication of a book.   One model is the approach C. Vann Woodward took to The Strange Career of Jim Crow. Woodward wrote and rewrote his book on race relations over the course of four editions between 1955 and 1974, responding to the various critics and new evidence.   Few authors have the opportunity to undertake so many revisions. But in lieu of that possibility, I've created this website. It includes reviews (both favorable and not), blogs that discuss the book, and the audio from several interviews. It also presents my remarks from various online exchanges that followed publication of the book. I not only welcome but encourage readers' comments.   Marc Egnal Contact me: megnal@yorku.ca     NOTE: Here's the source material for the Disunion series essay, "The Greenback is Born," published on-line by the New York Times, February 27, 2012.   ATTENTION PROFESSORS: This web site, which brings together all the reviews of a controversial book, lends itself to an excellent undergraduate exercise. Here's the essay assignment I gave to my second-year students.