Open Midnight weaves two parallel stories about the great wilderness—Brooke Williams’s year alone with his dog ground truthing wilderness maps of southern Utah, and that of his great-great-great-grandfather, who in 1863 made his way with a group of Mormons from England across the wilderness almost to Utah, dying a week short. The book is also about two levels of history—personal, as represented by William Williams, and collective, as represented by Charles Darwin, who lived in Shrewsbury, England, at about the same time as Williams. As Brooke Williams begins researching the story of his oldest known ancestor, he realizes that he has few facts. He wonders if a handful of dates can tell the story of a life, writing, “If those points were stars in the sky, we would connect them to make a constellation, which is what I’ve made with his life by creating the parts missing from his story.” Thus William Williams becomes a kind of spiritual guide, a shamanlike consciousness that accompanies the author on his wilderness and life journeys, and that appears at pivotal points when the author is required to choose a certain course. The mysterious presence of his ancestor inspires the author to create imagined scenes in which Williams meets Darwin in Shrewsbury, sowing something central in the DNA that eventually passes to Brooke Williams, whose life has been devoted to nature and wilderness.