Students often ask teachers, "Which secondary books should I read?" To which I often reply, "None. The primary works themselves give you the best and most authoritative guidance there can ever be. Read and reread them. Each will teach you how it wants you to read it, without help from inferiors. Prefer its severe mysteries to all secondary elucidation. Shakespeare is sweeter, and nobler than all who have ever written on him-even Goethe said so. Lincoln could say in a sentence what others writing on him explain in a book-and fail to. Pascal says things one memorizes in an instant and chews on for life. In comparison with such works, all secondary ones are very secondary. The exceptions (e.g., Thomas Aquinas on Aristotle, Alfarabi on Plato, Strauss on Machiavelli, Heidegger on Nietzsche) only prove the rule; secondary works that are also primary, which would be of interest to their subjects (as Thomas would be of interest to Aristotle), are even rarer than simply primary works."
It is almost always better to stick to your primary author, to read and reread him rather than turn to commentators or critics. It is also better to read some other book by your author or a work by another primary author: It would be a shame to delay your meeting with Tolstoy or Thucydides, Moses or Nietzsche, or even Keiler and Halifax, until you are thirty. Life is short, friendship precious, and youth decisive. Only primary books, such as one might select for a summer among mountains reached by backpack alone, favorites one is happy to reread till they rail apart, are worth lugging through life.
This being said, there are reasons for reading a secondary work. After one has read and studied a primary work, tried to discover what it teaches or what it shows, lived with it and questioned it, and arrived at a provisional account of it or a provisional confusion, one is naturally curious to compare what one has found with what other readers have found; after all, they may correct one, improve one's understanding, or give one an example of excellent reading. Even a reading inferior to our own can be instructive, for often when we say "no," "no," "no" to an interpretation we begin better to understand the "yes" our noes presuppose or see the "yes" our noes are still groping for. Sometimes very bad readers instruct us better than mediocre ones, much the way the visit of an alcoholic uncle instructs us more vividly than years of parental moderation. Especially when we are young we seem to move toward the truth by vehement rejections of the false.
Only later, if at all, do we realize that we should seek out the strongest opponent and critic of our favorite views, indeed that we have no right to our favorite views if we do not do so, for they are only, at best, right opinions if we cannot state the strongest reasons not only for them but against them. When we are young, we are more likely to be skeptical of everything except ourselves, like Descartes. In views that strongly oppose our favorites, we may find a devil's advocate to keep in check the true devils that we are.
Of course only a good interpretation pleases thoroughly, for it not only gives us a better understanding of some text and the things the text is about but strengthens what is best in us, the desire to learn. It does so not only by gratifying this desire with a particular bit of understanding but by enlisting all our powers of imitation. Bad examples can be instructive, as we said, but good ones can in addition be imitated, which is one reason we owe more to a moderate father than an alcoholic uncle.
The example of a bad driver teaches us to stay out of the ditch, but a good one teaches us, in addition, how to get to Santa Fe on time and fresh. We are right to feel gratitude to good examples and none toward bad ones, for good ones get us further toward our goal. The better they are, the better they are for us. A father who is not an alcoholic, not cruel, not lazy and not-cowardly is better than one who is, but not as good as one who is moderate, gentle, diligent, and courageous. Freedom from vice is not yet virtue. "At least he's not vicious" is not what we say about a virtuous man.
One test of the difference is whether the man or the example is worth imitating. Nothing merely "satisfactory" stirs imitation. We may approve of those who are correct, free of error, and blameless, but we do not emulate them. No kid with any spunk dreams of becoming a utility shortstop with a .240 batting average or of writing like the New York Times. What is average cannot be an aspiration. The trick is to combine the careful and the noble, the "satisfactory" with the excellent, the correct with the great.
What is worth imitating is also worth surpassing. In fact, what is worth imitating would not be worthy if it did not want you to surpass it. Just as the best teachers want their students to say something on a text or in a paper that is better than what they have heard from their teacher, so the best interpreters want their readers to best them. Intellectual competition has this peculiarity, which makes it different from all others; in it the loser can win as much as the winner, for when the loser sees how the winner's interpretation is better, he shares equally in the fruit of victory, understanding.
There are then good reasons for reading secondary works, but which ones should one choose? First, I would suggest reading only ones that acknowledge they are secondary. If the author's name is spelled larger than, say, Shakespeare's, or if the marquee says Polanski's Macbeth instead of Shakespeare's, seek elsewhere; the man is a fool or a usurper. Among secondary books that do acknowledge their secondary character, you must also choose. I suggest that you find a passage on a subject you know very well; if the author writes well of it, what he says elsewhere may be worthy.
Above all, as you read a secondary book ask yourself "How would the author feel if the author of the work he's writing on appeared? How would this author feel if Shakespeare read his book, gave a guest lecture in his class, or asked to meet him for conversation?" If the author would be hostile or contemptuous, avoid him; if he would blush, he has not lost all virtue; but only if he would be delighted to meet Shakespeare is your secondary author worth further reading. The only professors of Shakespeare who are worth reading are ones who are students of Shakespeare. You can always learn something from the others but not what you most desire or what is most akin to Shakespeare himself. He sought wisdom in the important matter of life. A seeker may find nothing, his account may be wrong, but no finder was not first a seeker.
Such seekers naturally cherish their living and dead friends. When they read together, they forget the age, especially ours, which is characterized, among other things, by the fact that perhaps 90 percent of all secondary writers who have ever written are now writing. When they read, they choose only books fit to be read aloud with others or taken on solitary daily walks, happily solitary, indeed not entirely solitary.