The qualities of character and mind that go to the making of great teachers resist generalization. Certainly, as the editor of this collection of essays in reminiscence notes, there are some things common to all of them: "love of their subject, an obvious satisfaction in arousing this love in their students, and an ability to convince them that what they are being taught is deadly serious." Beyond these it is almost useless to argue that other gifts and skills are necessary: There are too many kinds of students and schools and colleges self-saddled with too many differing missions to allow "great teachers in one kind of institution to be much more than adequate in others.

It is plain that the professors commemorated in these descripitions were blessed with a teacher's most potent stimulus: avid students of unusual gifts and sensibility. But in relatively few undergraduate colleges have such students existed, now or at any time. For the most part the teachers in Joseph Epstein's collection, assured that their pupils literally ached for success in their academic work, had to be nothing more than themselves, out loud. Histrionic, irascible and self-regarding, many of them seem to have used their seminars and classes as little more than showrooms in which to polish and refit their notions and theories.

Moreover, all of them, from Edmund Wilson's great master Christian Gauss to John Wain's Oxford don C. S. Lewis, resist effective reminiscence: That is, there is in every case something utterly elusive -- some inarticulate residuum of inspiration, example, aura, voice, method, which serves to make it impossible for their essayists to convey to us, in terms really compelling, what it was that made their students admire them. It is as though we are visitors to their seminars whose entering presence constitutes intrusion. We are the committee, let us say, on tenure; we enter the room; all is somehow changed.

What these teachers accomplish is largely, it appears, adventitious. Their pupils remember, are moved, are provoked, are inspired, but only rarely in ways intended. But this -- if the teacher is to qualify as great" -- seems to be enough. Wilson on Gauss: "I knew from my own experience how the lightly dropped seeds from his lectures could take root and unfold in another's mind." Another of Gauss' pupils, exhilarated in the notion that his "doctor's thesis" was propounding original ideas, later found "the whole thing in germ in his old notes on Gauss' lectures." Morris Cohen, Sidney Hook's philosophy professor at CCNY, worked, Hook says, unselfconsciously, in another way: dispatching his students' answers and queries thus: "with a rapier or a sledgehammer . . . Those not bleeding . . . enjoyed watching others bleed." Alfred North Whitehead in 1934, at Harvard, "offered his wisdom to us in the form of amiable chats."

The small residential liberal arts college imposes certain different requirements on its professoriat -- different, that is, from those under which most of Epstein's subjects must labor. Undergraduates are remorselessly shrewd in their assessment of their teachers as people; and if their teachers do not themselves exemplify -- somehow embody -- the good that the organized study of their disciplines promotes, then the whole business is often a farce. This is probably regrettable; but it is true nonetheless.

These masters for the most part are exempt from such criteria of judgement. For the same reason that this book's value is an absorbing reminiscence rather than as useful commentary, these professors' entitlement to their students' gratitude is singular, not to be emulated, and not, certainly, to be found again.

In his preface to "The Nigger of the Narcissus" Joseph Conrad insists that the fundamental object of the novelists is "to make you see." The best teachers, in ways as various as themselves, are able to make their students see: to see what is good or useful in what they teach, and to make that seeing a habit.

These essays make plain the impossibility of our seeing, except dimly, the nature of the masters' gifts to their pupils.