“Shelley, the author of some infidel poems, is dead,” went the first impeccably scornful obituary of the poet. “Now he knows whether there is a God or no.” This was 1822. For the next 100 years, the irrepressible forces of prudery and good taste conspired to transform this fulminating rebel, who sought to bring about the spiritual regeneration of mankind, into an innocuous lyricist of beauty and nature, and to excuse “Queen Mab,” “The Mask of Anarchy,” and “Prometheus Unbound” as boyish indiscretions. Thankfully, literary history has since been revised, and this grotesque bowdlerization is now the stuff of ridicule.

Most modern readers derive their image of Percy Bysshe Shelley the man from Richard Holmes, whose 1974 biography “Shelley: The Pursuit” (NYRB, 880 pages, $22.95) restored to his subject not only the anarchism, the godlessness, and the rampant sexual cavorting (at least six children by three women in under 30 years, not to mention the copious extracurricular philandering), but also the temper, the mawkish self-dramatization, and the egomaniacal brutishness. Short of telling us that Shelley was a faithful monarchist who wrote verse extolling the institutions of marriage and private property, one wonders what the contemporary biographer will come up with by way of novelty — or at the very least, original emphasis.

Ann Wroe’s “Being Shelley” (Pantheon, 390 pages, $30) is an admirable, if at times rather skittish, performance. Her aim, she makes plain from the start, is “to write the life of a poet from the inside out: that is, from the perspective of the creative spirit struggling to discover its true nature.” She proceeds to trace her subject’s “quest for truth” with a little help from the Hippocratic elements, partitioning the book into sections entitled Earth, Water, Air, and Fire. The arrangement, in other words, is not chronological but thematic. A chapter will begin in the realm of the literal and the concrete, telling us, for example, of Shelley’s childhood antics: “His sisters remembered him, as a boy, parading through the kitchen with a blazing stove and setting the butler alight.” At length, the figurative implications accrue — “From chemistry to philosophy was but a small step for him: changing substances, minds, the world, by the agency of fire” — until Ms. Wroe is ready to attack the poetry head on.

Ms. Wroe’s disregard for chronology does not always make “Being Shelley” the easiest book to get along with. Like a bleary-eyed tourist, the reader is whisked back and forth across Europe, alighting now in London for a brisk familial feud, now in the French Alps for a revelation of nature’s indifference to the ways of man, as Ms. Wroe indefatigably checks off each stop onShelley’s frenetic psychical itinerary. At times, one may begin to tire of these fits and starts of personality, and long instead to feel simply the steady pressure of a self, the pleasure afforded by more conventional, straightforwardly linear biographies.

Yet on the whole, Ms. Wroe has chosen an ingeniously appropriate form for the presentation of her subject’s 29 years and 11 months of tumultuous existence, for what are Shelley’s poems about if not the human propensity for myth-making, the impulse to uncover the archetypes that lurk behind life’s diminutive happenings? Of course, his life was not a visionary poem. Ms. Wroe’s appreciation of this fact is more subtle than one might at first realize. She delicately interprets “Hymn to Intellectual Beauty,” for example, in a paragraph that gives credence to the power of the poet’s retrospective imagination, without quite taking the congenitally mendacious Shelley at his word:

Of all those childhood experiences, real or imagined, one had marked him above all others. This was his sudden awakening, on one particular morning, to the shadow of the Spirit of Beauty in the world. After this he became a fighter for liberty and an insatiate seeker after Beauty, Love and Truth, obsessions that never left him.

That “After this,” indulgent yet detached, finely satirizes the histrionic notion of causality implicit in Shelley’s self-mythologizing.

John Updike once complained that except for “a few phrases from his letters and an odd line or two of his verse, the poet walks gagged through his own biography.” Not so Ms. Wroe’s Shelley, with his profusion of notebooks, cancelled verses, and reported conversation, is a roaring cataract of garrulousness. Indeed, her commentary sometimes has to strain in order to be heard over the racket, an exertion that cannot always be counted on to bring out the best in her prose: “Pestered and wounded by thoughts that snapped at his heels like hounds, he stumbled through life as through a forest of thorns that tore his pale, exhausted flesh.” At such moments, when the writing swells to its most uselessly tumescent, one almost feels as though Ms. Wroe wants to turn Shelley back into the idealized figure of the Victorians.

If “Being Shelley” does justice to the man who partook of “the eternal, the infinite, and the one,” it often does so at the expense of the man who wrote in the preface to “Prometheus Unbound,” “The mass of capabilities remains at every period materially the same; the circumstances which awaken it to action perpetually change.”Events are located too persistently inside his head for things to be otherwise. It is no small service, however, to be given a life of Shelley that does not reduce its subject to the status of a docile marionette in the immense puppet show of early 19th century power struggles, the result of much theory-soaked academic criticism. Instead, we have a book in which every concern is subordinated to that of poetic greatness, and every response comes second to that of awe. As a result, we are presented with a Shelley in whom it is easier to discern the thing he wanted us to see all along: namely, ourselves, “under a thin disguise of circumstance, stript of all but that ideal perfection and energy which every one feels to be the internal type of all that he loves, admires and would become.”

Mr. Harvey is on the staff of the New York Review of Books.