Law and Literature: A Misunderstood Relation (Harvard, 371 pages, $25) is a wonderfully original and instructive study of what literature has to teach about the law, the methods of legal argument, and the interpretation of statutes and the Constitution. It is a demanding, rigorously academic work. Yet I can recommend it to general readers and non-lawyers (if there are any left) for the depth of its insights into jurisprudence and literary classics, and for its vivacious style, which propels the reader through many subtle arguments.

The book is framed as a response and extension to the "law and literature movement," a growing academic specialty that recently has produced several books and numerous journal articles by literary law professors and legal-minded literary scholars. The movement has two main flanks. The first uses the trials and other legal proceedings that are central features of many great works of fiction (such as The Merchant of Venice, Bleak House, and The Brothers Karamazov) to elucidate real legal institutions. The second borrows literary criticism’s concern with problems of interpretation to address problems of legal interpretation (in interpreting the Constitution, should judges care about the Framer’s intentions or only their own reactions—their "contemporary values"?).

As it happens, both flanks are heavily manned by legal radicals, some of them members of the "critical legal studies" movement who want to subvert traditional legal institutions and replace them with boldly political, economically redistributive forms of "justice." They are strongly attracted by contemporary "reader-centered" styles of literary interpretation, which emphasize the reader’s subjective reaction to literary texts: they want judges, like readers of poetry, to read their own experiences and feelings into laws and the Constitution, even if (especially if?) this leads to sharp departures from what the legislators or Framers had in mind.

Mr. Posner’s treatment of the "literary lawyers" (not all of whom are radicals) is scrupulously fair and respectful, and devastating. Poems and laws are written and read for different reasons: for example, poetry is private and persuasive while laws are public and coercive. While a poet’s intentions are frequently irrelevant to understanding and enjoying a poem, that is no license for judges. Great literature—that which survives the "test of time"—addresses universal themes and proceeds through moral ambiguity or at least nuance; even fictional works by lawyers about legal proceedings (Kafka’s The Trial and In the Penal Colony) employ the law metaphorically and with broad license. Quibbling over legalisms (was Billy Budd’s drumhead court-martial lawful under eighteenth century British naval law?) adds little to our appreciation of such works, and attempting to extract political manifestoes from them obliterates the very qualities that make them great literature.

Mr. Posner’s adversaries are hopelessly outmatched in these arguments, but they are only supporting characters in a larger and more interesting drama—the author’s own exegesis of the relation of literature to law, propounded in a series of arresting, brilliantly interwoven interpretations of dozens of literary works from Homer and the Greek myths through several twentieth century novels and poems. He acknowledges, indeed asserts, that law functions to discipline and disappoint the Romantic impulse in man, forcing a mature sense of limits on man’s youthful visions of a life of infinite possibilities (which is, ultimately, what our modern Rousseaus of legal scholarship detest about the law). But he shows that most great literature concerned with the law portrays this function as necessary and worthy. That man’s individuality should be constrained is an aspect of the human condition, not (at least not necessarily) a contrivance of social repression and exploitation; enduring literature reflects this enduring truth.

And the classics show that law serves this function well neither by rigid application of formal rules nor by permitting judges wide discretion to do ad hoc justice. Formal laws may have unjust results unless tempered by equity, as we see in Measure for Measure. But strict adherence to formal rules often is necessary to do justice, as in protecting minorities from the discretion of majorities: legal technicality was Shylock’s shield and sword in Christian Venice—until he pressed his advantage to unjust extremes, whereupon Portia turned the tables and used her own clever technicality to retrieve ultimate justice. And the formless equity procedures portrayed in Bleak House may produce injustice through uncertainty and eternal delay. Law embraces both formal rules and equitable discretion in a state of constant tension, and in the hardest cases (as in Antigone and Billy Budd) there is no happy choice between them.

Mr. Posner believes literature also holds important practical lessons for lawyers and judges about rhetoric and the craft of writing. Here he contrasts the detachment, balance, and concreteness of great literature with the euphemism and windy hyperbole of modern judicial opinions. His arguments are illustrated by delightful analyses of several rhetorical masterpieces from both fields, including Yeats’s The Second Coming, Antony’s funeral oration in Julius Caesar, Justice Holmes’s dissent in Lochner v. New York, and snippets from the opinions of other great judges.

A short final section of Law and Literature discusses the regulation of literature by the law of defamation, censorship, and copyright. The highlight is Judge Posner’s suggestion that copyright law might be narrowed to permit greater literary copying: Shakespeare’s practice of "creative imitation"—borrowing heavily from contemporary works but embellishing and transforming them—would be unlawful today within the time limits of copyright. Characteristically, he ties this argument to his book’s broader themes. The modern equation of creativity to spontaneous originality is a legacy of Romantic individualism; the earlier, more realistic notion of creativity, under which Shakespeare flourished, recognized that authors, like other men, are not islands.