The concept of the seven-day week is a powerful idea that shapes social behavior and commerce. It is a taken-for-granted aspect of social life—so much so that historians have mostly neglected its history. I can only think of two other books that focus on the week: Eviatar Zeruvabel, The Seven Day Circle (1985), and Alexis McCrossen, Holy Day, Holiday (2000). Henkin’s book differs from Zerubavel’s in not emphasizing Jewish tradition. In contrast, The Week is complementary to McCrossen’s work—whereas McCrossen emphasizes the American idea associated with Sunday, Henkin focuses on the social, educational, and commercial rhythms associated with the other days of the week.

Henkin begins by stating the obvious: the week is not tethered to any natural phenomena. The idea that it is one quarter of a lunar month is not accurate, because months are 29.5 days long. While many assume that the week is a product of Jewish tradition and then adopted and promoted by Christianity, Henkin correctly demonstrates that the history of this unit of time is far more complicated and multi-cultural. For instance, the seven-day cycle can be linked to ancient astrology, with each day having a different ruling celestial object. Indeed, this heritage is still embedded in the names of days in European languages; for example, Sunday in English or mercredi in French is short for that Latin form of “Mercury’s day.”

While the history of the seven-day week might have ancient roots, most of the book is about the distinctive rhythms associated with the week in American society. He begins with a discussion of the dominical week—the week anchored by Sunday. This is associated with the Sabbatarian week, but with Sunday being treated as the Sabbath by New England Calvinists, in particular. While Sunday became an anchor of the week, Henkin shows that each day of the week gained its own significance that is not only documented in diaries but also in doggerel indicating activities associated with different days, such as Monday being washing day.

It at this point that Henkin develops the argument that in nineteenth-century American society the week developed complex rhythms associated with a variety of practices and institutions. These included weekly paydays, the school week, weekly markets, meetings, and the publication of newspapers.

Alongside these emerging social rhythms were personal practices, such as diary keeping, that became structured by the publication of journal books structured according to the week. As Henkin points out, this was a departure from the form of the almanac, which had been quite popular for over a century. Almanacs organized their dates according to the month, but the blank journals for keeping a diary were organized by the week.

As the week became more habit, it also was entwined in the growing interest in creating rational systems of timekeeping in the late nineteenth century. As Henkin points out, this was a period of reforms that are still with us, such as time zones and anchoring global time to the prime meridian. It was also a period in which there were reformers who tried to organize the different rhythms of year, month, and week to repeat consistently from calendar year to calendar year. Henkin explores several of these schemes, including examples that were briefly implemented, like the Soviet Union’s experimentation with five-day cycles. It is in this chapter that I have my one quibble with Henkin’s argument. After many examples of how the seven-day rhythm became embedded into social habits, he concludes: “The failure of calendar reform stemmed from the week’s origins and foundations” (p. 177). He first argues persuasively that by the end of the nineteenth-century, educational, social, media, and commercial practices meant that there was far more to the week than a religious foundation. But then he suggests that its persistence was religious. To me, this conclusion underestimates the power of the social habits this book nicely documents.

Henkin ends the book by musing about whether the week will persist in its present form. After all, technology has to some extent freed work, educational, entertainment, and commercial cycles so that they no longer are tethered to brick-and-mortar institutions. On the one hand, with the forces of capitalism encouraging a 24/7 society, Henkin’s question seems reasonable. On the other hand, with the complex web of social and commercial rhythms and how they are embedded in things (e.g., diaries) and habits (e.g., sports on weekends), the week is likely to persist.