“A book unwritten is more than a void,” George Steiner observes in a prefatory note to his new essay collection, “My Unwritten Books” (New Directions, 192 pages, $23.95), a book — yes, written and now published — on seven projects that the otherwise astoundingly prolific Mr. Steiner, a former don of comparative literature, never quite managed to bring to fruition. “It accompanies the work which one has done like an active shadow, both ironic and sorrowful. It is one of the lives we could have lived, one of the journeys we did not take.” Rather than leaving the basic itineraries for these neglected journeys in the notebooks in which they were initially drafted, or as computer files tucked away on his hard drive, Mr. Steiner has chosen, for better but often for worse, to bring them into the public eye.

The range of subjects that Mr. Steiner covers mirrors the intellectual breadth he has demonstrated as a scholar and critic over the past five decades in such influential books as “The Death of Tragedy,” “In Bluebeard’s Castle,” “After Babel,” and other works of considerable literary ambition. Each chapter presents a topic — the extraordinary career of British biochemist and Sinologist Joseph Needham, the envy-inspiring work of 13thcentury Italian physician and poet Cecco d’Ascoli, the vexed question of Jewish identity, and man’s relationship to animals, to name a few — and, after offering a lengthy disquisition, attempts to explain why Mr. Steiner finally abandoned the project (e.g., “too near to the bone” in his chapter on d’Ascoli, lack of “raw introspection” and “guts” in “Of Man and Beast”). Whatever personal reasons he cites, however, it seems just as plausible these projects were abandoned because none of them could stand any kind of intellectual scrutiny.

Each essay gives the author a chance to draw on his impressive knowledge. He cites a rich array of intellectual and cultural luminaries, figures whose cameo appearances — more often than not they are left to stand on their own without much in the way of illuminating explication — are clearly designed to lend a bit of gravitas to Mr. Steiner’s occasionally less-than-grave observations. Thus, we have “Copernicus, Kepler and Darwin” in one chapter, “Cicero, Virgil and Quintilian” in another, and “Plato, Descartes, Spinoza” in still another. (In his final chapter, Mr. Steiner employs a grating strategy, attaching an indefinite article to the names he cites, ostensibly to underscore their representative status: “a Kierkegaard or a Nietzsche or a Wittgenstein” and “a Plato, a Gauss or a Schubert.”) In other chapters, when he cites from his selected masters of Western literature (lines from d’Ascoli, Goethe, and Paul Celan), he leaves them in the original without providing an English translation, as if to suggest — using the same snobbish logic that presumes the reader’s ability to identify the entire range of his dramatis personae — that his readers ought to be able to read verse in Italian or German.

Mr. Steiner, who was, as he tells us, “brought up trilingually,” has often called attention in his scholarly work to the finer nuances of language and society. In “My Unwritten Books,” he offers a chapter, certainly his most daring, on “The Tongues of Eros,” an insipid consideration of what it means to make love in different languages. “Sex is spoken and listened to,” he writes, “aloud or in silence, externally or internally before, during, and after intercourse.” For Mr. Steiner, who has “been privileged to speak and make love in four languages,” there exists an underlying grammar of sex (“the orgasm is an exclamation mark”; “shared orgasm is an act of simultaneous translation”), and in different languages, that grammar expresses its own set of distinctions.

Unfortunately, where Mr. Steiner has elsewhere exhibited linguistic subtlety, here the points he makes are crude at best: “To make love in German can be taxing,” or “To make love in Italian is to know that certain days run to twenty-five hours,” or, still worse, “In Tulsa, Oklahoma, my glorious ebony partner hummed at me: ‘Baby, you haven’t seen anything yet.'” (Mr. Steiner’s purported reason for abandoning this particular topic: “Indiscretion must have its limits.”)

Mr. Steiner’s encyclopedic knowledge, on dazzling display in other work, is merely an impediment here. At times, his efforts to wow reach the level of self-caricature. As he notes in his chapter “Of Man and Beast,” commenting on his dog Ben, “He balks at brass bands and emits a low growl when Ravel’s ‘Bolero’ comes on. He is at peace with Hayden and all manner of baroque instrumentalists.”

I remember, from my graduate student days, a professor, a self-avowed polyglot and polymath like Mr. Steiner, who was known to pose questions at public lectures that required the kind of immense erudition that only a wunderkind Renaissance philosopher could possess. His questions, peppered with direct citations from primary sources in the original Latin, French, German, and Italian, would sometimes take nearly as long to formulate as it took the visiting lecturer to deliver his or her full lecture. It didn’t matter on which subject the poor lecturer happened to be presenting — it could be the history of contemporary Bangladesh or the theories of Sir Isaac Newton — all trains of thought inevitably led back to Herodotus, Pico della Mirandola, and Hegel. Was this professor, we would ask ourselves, a true genius or, as the critic Joseph Epstein has suggested of Mr. Steiner, merely “a genius mimic” capable of giving “an incomparable impression of the world’s most learned man?” Had this book, too, remained unwritten, we might be less inclined to ask the question at all.

Mr. Isenberg teaches literature, film, and intellectual history at the New School. His criticism has appeared in Bookforum, the Nation, the New Republic, and elsewhere.