I wrote the book’s preface in the expectation that it would draw a potential reader into a deceptively familiar subject. The global shutdown in 2020 exposed all sorts of odd and interesting things about our relationship to schedules and calendars, turning us all into philosophers and sociologists of time. So I tried to mobilize that consciousness as a way of inviting people into thinking of the week as a powerful but perhaps fragile human construct and leading them on a tour of its history in the United States over the past couple of centuries. A reader who begins with the preface is likely to understand (and ideally share) the curiosity that drives this inquiry.Other kinds of readers might be drawn to other sections. Readers who have never considered why we still count continuous cycles of seven days, despite its inconvenience, might be most intrigued if they opened to the pages in Part Four (around pp. 170-178) where I recount some of the reform efforts that failed to dislodge the week from its awkward perch atop the other calendar units.Readers who are surprised by the claim that the modern week was the product of things other than labor and religion, might be drawn to Part II, where I survey the varied and unsuspected places where weekly habits took hold in the early 1800s.I would hope that another kind of reader would alight upon the pictures of almanacs and pre-formatted diaries (around pp. 124-30) and reflect upon how our mental maps of time connect to their visual representation.But kindred spirits might recognize most clearly what I’m up to if their first brush with book focuses on Part III, titled “Does Anybody Really Know What Time It Is?” More than anything else, the question of whether people know their place in the weekly calendar – and why they care – holds the key, I think, to the mystery and the power of seven-day timekeeping.I think a study of the week can convey two important lessons about the history of timekeeping. First, that time units that are culturally relative and rooted in human artifice can be as powerful as those that are universal and appear dictated by astronomy or biology. And second, that the role of human artifice in the history of timekeeping is not just about mechanical devices or technological innovations. Rather it is a story of conventions, laws, economic relations, cosmological beliefs, unconscious habits, and quiet social agreements.