For critics who got into criticism because they revere books, it’s a problem: How do you properly take notes for reviewing if you can’t bring yourself to deface a book by writing in it? “I know some people regard writing in books as a sacrilege, but it’s unavoidable in my profession,” observes New York Times and Salon.com critic Laura Miller. “At minimum, you need a way to flag important points and the passages you may want to quote, as well as to jot down any thoughts of your own.”

In a post at her blog, Miller discusses how she developed her own methods, including consulting with colleagues such as the Times‘ Dwight Garner: “Hesitant to deface the book itself, he’d flag passages with a tiny dot in the margin. You wouldn’t notice these dots unless you were actually reading the book, as opposed to leafing through it, but you can find them when you’re looking for them….”

For a while, MIller says she preferred to keep notes in a steno pad because “Steno pads are about the same size as a hardcover book, which makes them easier to tote around with it than a letter- or legal-sized pad.” But then, while researching for her book about C.S. Lewis, she came upon a letter Lewis wrote describing his methods: “I begin by making a map on one of the end-leafs: then I put in a genealogical tree or two. Then I put a running headline at the top of each page: finally I index at the end all the passages I have for any reason underlined….”

Now, Miller has adopted his methods. “True,” she says, “the book is ruined for other readers after this, but if I intend to keep it, in some ways it’s even more useful to me. I can almost instantly find passages that I dimly recall reading years earlier. Doing this sometimes makes me feel selfish and profligate, because I do wind up discarding most of the books I review. (I live in a small apartment.) I try to remind myself that there’s a long history of writers’ marginalia and no one loved books more than C.S. Lewis did. If he could reconcile his conscience to it, so can I.”