The historians are concerned. We now live in a post-truth world, one in which “alternative facts” hold freight while inconvenient truths can be dismissed as “fake news.” In this “age of disinformation,” as Princeton historians Kevin Kruse and Julian Zelizer characterize it, nefarious actors distort the historical record without compunction. The vanishingly thin line between fact and fiction, truth and untruth, Kruse and Zelizer insist, sits at the center of the interlocking political crises in which Americans now find themselves. Advertisement Now Kruse and Zelizer have assembled some of their most esteemed colleagues to set the record straight. Their new...