BOOK REVIEW / NONFICTION : Deconstructing That Cursed Shakespeare Play : WITCHES AND JESUITS: Shakespeare’s Macbeth <i> by Garry Wills</i> ; Oxford University Press $19.95, 205 pages

Garry Wills sets up a riddle on the very first page of “Witches and Jesuits”--”If ‘Macbeth’ is such a great tragedy,” he asks, “why do performances of it so often fail?”--and then he devotes the rest of his book to solving it.

“Macbeth,” Wills explains, is regarded as a cursed play in theatrical legend and lore. Even if actors manage to avoid the misfortune, mayhem and death that have attended earlier productions, they are doomed to artistic failure on the stage: “Nobody has ever succeeded as Macbeth,” critic Kenneth Tynan wrote. And so superstitious actors refer to “Macbeth” only as “the Scottish play” to avoid speaking its name out loud.

“Do I make ‘Macbeth’ too weird?” Wills ponders.

But, as we soon learn in “Witches and Jesuits,” Wills has turned his attention to “Macbeth” for quite a different purpose: He argues that the play is mishandled by modern actors and directors, and misunderstood by modern audiences, because we no longer appreciate its historical resonance or its inner meaning. And he takes it upon himself to explain what is really going on in “Macbeth.”

Wills says “Macbeth” is actually “a Gunpowder play”--that is, Shakespeare uses the story of Macbeth’s murderous conspiracy against the Scottish crown as a way of chronicling (and commenting upon) the history of Guy Fawkes and the Gunpowder Plot of 1605, a conspiracy that tried to assassinate King James I and destroy the government of England by blowing up Parliament.

“ ‘Macbeth’ looks like a different play,” Wills insists, “when we consider it in this context.”

Wills is best known, of course, as an elegant political biographer (“Nixon Agonistes”) whose points of reference run to the classics. But his book on Macbeth is hardly a departure from his political writings or his literary tastes; indeed, Wills uses the text of “Macbeth” to explain Renaissance politics and history in contemporary terms.

Wills harks to the early 17th Century, when “a religious cold war existed between England and papal Rome” and the Protestant throne of England narrowly (and rather miraculously) avoided overthrow at the hands of shadowy plotters suspected to be agents of the Pope. A Jesuit might be regarded the same way that a communist was regarded in the ‘50s, Wills suggests, and gunpowder was as every bit as fearful as the atomic bomb.

“Coming to grips with (the Gunpowder Plot),” he writes, “posed some of the same problems Americans experienced in the shock after Pearl Harbor, or after the execution of President Kennedy.”

Thanks to an elaborate propaganda campaign orchestrated by the king himself, the miraculous defeat of the Gunpowder Plot was celebrated in ballad and broad sheet in Shakespeare’s day. But, as Wills convincingly demonstrates, “Macbeth” is a subtle, sophisticated and almost encrypted account of the very same story.

Wills decodes the text of “Macbeth” to show us how Shakespeare turned current events into popular entertainment that survives as classic theater. The witches and their conjuring of “Night’s black agents” are made to stand for Jesuitical plotters against Protestant authority, and both Macbeth and his lady are their traitorous but troubled minions.

What Wills does especially well is to point out the sometimes baffling lines of the original text and then parse them out in terms that we can understand. For example, when Macbeth declaims that “The wine of life is drawn, and the mere lees / Is left this vault to brag of. . . .” he is using language that his audience understood as a reference to the sub-chamber where the Gunpowder Plotters planted their explosives.

“ ‘Vault,’ ” explains Wills, “was the ‘grassy knoll’ of Gunpowder writings.”

Wills’ musings on Macbeth originated as a series of formal lectures at UC Santa Barbara and the New York Public Library. Now he has gathered together the threads of his curiosity--not only the text of Macbeth but also the props, costuming, stagecraft of the play as performed in Shakespeare’s day--to give us a vast historical tapestry.

His book is a scholarly, highly specialized and slightly eccentric effort, a true labor of love, but somehow Wills manages to convince us that a fresh reading of the old play has its rewards. And so love’s labor is not lost in “Witches and Jesuits.”