The eighteenth trump of the major arcana of the tarot is The Moon, which does indeed represent the nocturnal side of things. It is the sign of the imagination as it conjures both dreams and nightmares. The Moon is uncertain and even a bit dangerous, in the primal way that causes all animals to fear the dark, even if irrationally. It is exactly this twilight sensibility that Alberto Manguel was concerned with as he wrote The Library at Night, an exploration of mankind's relationship with its books.
The book is a series of essays regarding different facets of that literary relationship, "The Library as Space," "The Library as Shadow," "The Library as Survival," and so on, but he's not just referring to the library as a public or private institution (though that is discussed at some length). He's referring to any group of books, from the famed Library of Alexandria, to the more modest personal collection, to the single book that keeps a prisoner of war from going mad. Manguel asserts that books contain stories, yes, but even more, the story of books is our story, as they represent what we choose to collect, emphasize, and remember.
The tarot's Moon also represents the permeability of the boundary between past and present, and as the book examines how mankind has kept and cataloged its stories, the reader begins to see how the past comes to bear on the ways we let our stories live in and with us even today. The Library at Night is meticulously researched and its admirable scope brings a wealth of perspectives to bear on the topic, but true to the nocturnal bent of the title, the essays meander dreamlike through history and culture from the heights of Classical Greece to the depths of World War II to reveal their insights. This book is a rare gem for bibliophiles, as it's clear that Manguel is a reader whose passion matches the best of us, and the essays he's written not only justify our passion for the printed word, but demonstrate that it's perhaps that very capacity for invention and memory that makes us human.