Last week, critic and former Poet Laureate Robert Pinsky wrote at Slate about two marvelous snarky (and ultimately wrongheaded) takedowns of John Keats by his contemporaries. Part of their problem, he says, is that they ignored entirely the three rules of reviewing. Pinsky got them from some stylesheet he received from a magazine for which he was writing in the 1970s, but as he says:

I'd like to think that the three essentials for reviewers were invented by Aristotle, preserved by his students, and handed down for thousands of years by oral tradition. After all, before the review was an important category of journalism, before physical books, even before printing, readers must have asked other readers to report on works they had not yet read from scrolls or tablets.

The three rules he gives us, pulled from that stylesheet of yore, are simple:

1. The review must tell what the book is about.

2. The review must tell what the book's author says about that thing the book is about.

3. The review must tell what the reviewer thinks about what the book's author says about that thing the book is about.

These are very good rules, and ones I plan to bring into the classroom when I teach criticism later this fall. And it's surprising how many writers forget these: as Pinsky points out, many spend all their time on 1 and 2, but are too timid for 3; others sail right into 3, briefly hit 1, and ignore 2 entirely. The three together forces the reviewer to fairly evaluate the book and whether it works.

To these rules, though, I might add a few of my own:

4. Don't be wantonly mean, particularly when the effort is sincere. Those reviews are fun to read, sometimes, but they're more destructive than helpful.

5. Don't insult the audience. The fact that someone disagrees with you does not necessarily render you or him wrong. Books, and movies and other things we write about, are comprised not just of their own substance but yours; what you had for breakfast, or who you fought with or read over lunch, can sometimes profoundly alter the way you think about a work. And you'll probably look at it differently in a year, or ten. Publishing has a long memory. And so do authors.

6. Remember: It's usually better to start a conversation than close it down.