Rhetoric is heard," Yeats said. "Poetry is overheard." The truth of that statement and the friction created by J.M. Coetzee's noble effort to bring politics and poetry to terms is at the heart of his latest novel, "Diary of a Bad Year."

Coetzee, a native South African who now lives in Australia, is regarded by many as the English language's greatest living novelist, and despite that Nobel Prize gathering dust on his shelf since 2003, he can't be accused of complacency.

"Diary of a Bad Year" is his most technically ambitious work, a three-tiered concoction that attempts to meld essay, fiction and confessional memoir. (The main character is an aging writer named Coetzee who refers to a novel called "Waiting for the Barbarians," the book that, in fact, brought international fame to the real Coetzee.)

There is a plot, although it takes a while to kick in. The fictional Coetzee is asked to contribute some chapters on cultural and political subjects to a German publisher for a book titled "Strong Opinions" (a gibe, perhaps, at Nabokov, who used the same title for his collected interviews and loathed the use of political themes in fiction). That's the first layer; the second reads like a transcript of the author's personal thoughts over the period in which the essays were written -- this constitutes the diary of the title. The third stratum, written more in the form of a traditional novel, involves the author's evolving relationship with his Filipino secretary and, inevitably, a clash with her cynical and amoral boyfriend.

The three streams are presented on each page, one atop the other; the reader must quickly decide which is the proper way to read the book -- each thread all the way through or one page at a time, moving downward to the next layer. I opted for the second approach, which made the novel seem like the literary equivalent of the three-dimensional chess that Mr. Spock played on "Star Trek." While frustrating at times, this method rewards by revealing Coetzee's extraordinary gift for literary counterpoint -- a talent not unlike that of Bach, the composer he most admires.

I fear I've made this sound more difficult than it actually reads; all three elements are compelling and are pulled together by themes both minor (an older man's lust for a younger woman) and major (the redemptive powers of genuine love and acceptance) with which readers of Coetzee's great recent novels, particularly "Disgrace" (1999) and "Slow Man" (2005), are familiar.

The elements are so compelling, in fact, that it's not easy to pin down precisely why they don't come together as a whole. Coetzee's technique isn't a gimmick, but the way it is used here sometimes seems gimmicky, a self-consciously postmodernist presentation of obviously anti-postmodernist ideas, particularly the relentless coarsening of language and music in the modern world. The rhetorical points presented by the fictional Coetzee range from the provocative (Why do political leaders who remained unruffled during decades of nuclear threat react with near-hysteria to "the pinpricks of terrorism"?) to the banal ("Democracy does not allow for politics outside the democratic system," which Shaw observed a century ago). Since they are all ideas that Coetzee has pursued at length in both his fiction and nonfiction, one wonders why they are being reprised here -- and, more to the point, why they are presented behind a shadow version of the author. No sooner, it seems, is any proposition asserted than its integrity is undermined.

In the end, "Dairy of a Bad Year," for all its careful craft, draws us in just to put us off again. You can hear Coetzee's unmistakable voice, but this time around you may have trouble overhearing it.

Allen Barra reviews books for Salon.com and was a 2005 finalist for the National Book Critics Circle Nona Balakian Citation for Excellence in Reviewing.