The index reifies it as a book, at the same time that the choice to foreground one topic or another might surprise even the author. And I was reminded, reading Duncan’s paean to them, ...

Do you still use book indexes? I am not a good person to ask, because I only use electronic books. It takes a few seconds to search a book for the precise word I'm looking for.

"Index, a History of the: A Bookish Adventure from Medieval Manuscripts to the Digital Age" explores the development of those things in the back of a book that many of us turn to for reference.

The engagement index shows not only what, but when, students are reading, so if they opt not to peruse the textbook until the day or night before a test, the professor will know.

INDEX, A HISTORY OF THE A Bookish Adventure From Medieval Manuscripts to the Digital Age By Dennis Duncan Illustrated. 344 pages. W.W. Norton & Company. $30. Before reading “Index, A History of ...