BOOK REVIEW : A Poet Launches His Grand Obsession : CATAPULT; Harry and I Build a Siege Weapon <i> by Jim Paul</i> , Villard $18, 272 pages

“ . . . balista, beugle, blida, bricole . . . “

Jim Paul, a poet-adventurer living in San Francisco, is a man under the spell of the catapult. He turned himself into an expert on the history and technology of catapults, the legend and lore, and even the “foliation of names” for this ancient weapon:

“ . . . calabra, engin a verge, espringale, fronda, fundibulum . . . . “

Then Paul enlisted the grudging assistance of his buddy, a cranky and fretful but undeniably brilliant tinkerer named Harry, and the two of them set out to build and fire a catapult. Harry pored over antique engravings in order to resurrect the long-forgotten craft of catapult-building, but Jim--ever the artist--was getting into “catapult consciousness” and, pursuing the authentic muse of the 20th-Century artist, applying for a foundation grant.

“ . . . manganum, martinet, matafunda, petrary, robinet, scorpion, and tormentum . . . . “

The story of the catapult that Jim and Harry built is recounted in “Catapult,” a book so zany in its conception, so eclectic and eccentric in its curiosities and so funny that I could not put it down.

From the moment that Paul hefts a chunk of ancient quartzite in the mountains of Utah (“The rock might let me feel some intimate connection with the immensities of the past”) and comes up with the notion of shooting it into the Pacific Ocean from a catapult on the spectacular headlands of Marin County, we find ourselves on a roller-coaster ride through the intellect and imagination of a poet in the thrall of a grand obsession.

As it turns out, Jim Paul’s idea exerts an irresistible charm--and that’s the real point of the book. When Jim and Harry venture into the industrial byways of the San Francisco Bay area to find the raw materials for their catapult--a quest of considerable color and interest in itself--they find that the workaday welders and drill-press operators, the purveyors of steel and beams and springs and cable, are enchanted by the project.

Even the foundation director whom Paul approaches for a $500 grant is easily persuaded that building and firing a catapult amounts to a work of art: “It’ll be a Conceptual Reconstruction,” Paul burbles, and the director laughs out loud but says yes.

Paul embellishes the yarn with ornate historical and philosophical decoration. He ponders the invention of the catapult by Archimedes, the siege of Jerusalem, the influence of ancient artillery on military architecture. He reveals that the catapult was “a kind of primitive chemical warfare” when used to throw a dead horse over the walls of a besieged castle. And he insists that the catapult was the decisive weapons technology of its time, likening it to the atomic bomb in our own era.

“The weapon’s range and invisible potency made modern empire possible,” he writes, “and transformed Western culture.”

At times, it appears that Paul has plumped up his book with asides and digressions in an effort to fill out the rather simple story of the catapult itself.

For example, he reminisces about his father’s experiences as the bombardier on a B-17 in World War II--and he muses, too, about his father’s golf game, a symbol of estrangement that later became an excuse for intimacy. And he leads us, almost incidentally, on a tour of some of the most picturesque sites in the Bay Area: Ft. Point, the Exploratorium, the Marin Headlands. But Paul is a gifted storyteller, and even when his mind wanders, I found myself perfectly willing to follow.

“Catapult” is, among other things, a lilting and graceful piece of writing by a man in love with language. When Jim and Harry succeed in fashioning the cross-arms of the catapult out of cannibalized truck springs, Paul pauses to reflect on the simple beauty of the machine: “Our first assemblies, I thought. To me they had a rightness, like simple sentences.”

At moments, it’s tempting to render his prose as verse, as when he reflects in passing on the destruction of the Second Temple: “With the altars of the temple broken and lost, / they made their sacrifices in prayer, / and felt with new force / the old grief of the prophets.”

The publisher of “Catapult” likens the book to “Zen and the Art of Motorcycle Maintenance” and calls it “a cult bestseller born and bred.” But Jim Paul appears to be free of such ambitions and pretensions--he recognizes that the catapult was “a project that most people either loved in a little-kid way or said sounded weird and dumb,” and I suspect that the book itself will evoke the same set of responses. Indeed, “Catapult” struck me as both lovable and weird, and all the kickier for it.

Next: Richard Eder reviews “Madoc” by Paul Muldoon (Farrar Straus & Giroux).