‘We like lists because we do not want to die,’ quipped the late, great Umberto Eco. The occasion for this remark was the opening of his 2009 Louvre exhibition, ‘The Infinity of Lists’, a dizzying exploration of listing activities over the last 5000 years. Curating the exhibition compelled the Italian polymath—who knew more than a little about such matters—to claim the list as ‘the origin of culture.’

Eco was not the only literary figure with a fondness for the humble list form. ‘Bare lists of words are found suggestive to the imaginative and excited mind,’ wrote Ralph Waldo Emerson, whose work is littered with enumerations. We also learned, upon her passing, of cultural critic Susan Sontag's self-described list ‘compulsion’. Curators of the born-digital Sontag archive at UCLA were baffled by the preponderance of lists on her hard drives: topics she planned (or hoped) to write about; listed records of correspondence (incoming and outgoing: who wrote what and when and to whom); pages of titles of films and images (viewing reminders? a canon of her favourite pieces? things to keep in mind?) and, of course, to-do lists, those gentle giants of administration that do so much heavy lifting for us, but whose burdens weigh us down.

Sontag's beguiling lists illustrate everything that this book is about. They show how a study of lists is a battle against entropy. When you start looking for lists, they are everywhere; when you start talking about lists, your eyes and ears are filled with suggestions and ideas. One's only recourse is to add these to a list of things to consult, to read, to think about. Sontag's archive shows that lists categorize, yet, at the same time, defy categorization. This is perhaps their essential feature. We typically think of lists as administrative: they organize thoughts, offer reminders (not always friendly), and help get things done. But they do so much more than this. Lists draw things together and allow us to forge connections between divergent items, placing them under a logic that is all our own. This seemed to be what so fascinated Sontag about the form. By making lists, she wrote, ‘I perceive value, I confer value, I create value, I even create—or guarantee—existence.’ This is strong language from someone not prone to exaggeration.