How would you sum up John Simon in one word? Ask any number of theater professionals and you'd likely get a vast array of colorful answers to that question, most of which probably couldn't be noted here. But I submit that the best description of Simon is "erudite," and this most valuable of his qualities is on ample display in the recently published collection John Simon on Theater (Applause Theatre & Cinema Books, 837 pp., $32.95).

This is not to say that Simon's masterly command of English and encyclopedic knowledge of theater will convince everyone of his worth as a theater critic or as a human being; the man has made many enemies for his frank (some say vicious) observations about productions, performers, and other theater practitioners. One may speculate at great length on how his abrasive, no-holds-barred style has impacted his career; ripples of suspicion were certainly felt earlier this year when he was unceremoniously dismissed from his long-held post at New York magazine and replaced by Jeremy McCarter, then the New York Sun theater critic and 50 years Simon's junior. But such concerns are academic and ultimately worthless. John Simon on Theater paints a portrait of a man who, with his perceptive eye, razor-sharp wit, and passion for the art form, has it all over most others in his field.

Simon, who now writes for Bloomberg.com, is revealed in the book's new material as possessing a heretofore unsuspected modesty; he offers a few sentences of thanks, a five-sentence author's note, and a small handful of 2005 postscripts informing the reader of predictions that didn't come to pass or initial impressions that hindsight and further exploration have since proven inaccurate. (These frequently involve his underrating of Stephen Sondheim scores). Those expecting a gossipy behind-the-scenes memoir along the lines of Frank Rich's Hot Seat will be sorely disappointed; Simon has chosen to once again let his reviews speak for themselves.

Take, for example, this critique of the composer of the 1998 Broadway musical The Scarlet Pimpernel: "Frank Wildhorn is essentially a pop composer, seated not so much at the piano as at the meat grinder, churning out endless vermiform lengths of elevator, cocktail-lounge, skating-rink, and beauty-pageant music. In them, the same trite phrases are repeated over and over, giving Chinese water torture ferocious competition."

Equally blunt is his appraisal of the 1979 Broadway production of Richard III, starring Al Pacino: "This production disproves two charges frequently brought against American companies in Shakespearean productions: that they cannot do accents and that they are incapable of ensemble work. In this Richard III there are accents aplenty -- every kind of accent you have ever heard in your life, except one that has anything to do with Shakespeare. As for ensemble work, everyone from star to walk-on -- absolutely without exception -- manages to give a bad performance. Such unheard-of consistence does make for an ensemble: an ensemble of horror, but an ensemble."

Some people might want to buy the book just to read Simon's (in)famous description of Liza Minnell in Kander and Ebb's The Act: "I always thought Minnelli's face deserving -- of first prize in the beagle category. Less aphoristically speaking, it is a face going off in three directions simultaneously: the nose always en route to becoming a trunk, blubber lips unable to resist the pull of gravity, and a chin trying its damnedest to withdraw into the neck, apparently to avoid responsibility for what goes on above it. It is, like any face, one that could be redeemed by genuine talent, but Miss Minnelli has only brashness, pathos, and energy."

Although this last passage is often cited as proof of Simon's cruelty, it does display his keen awareness and sense of purpose -- especially as followed in the book by his recounting of a discussion with Sabina Harbison ("the well-known Patagonian press agent") in which he defends his comments on the grounds that all performers must make their looks work for them instead of against them. He makes the argument persuasively. While it won't change many minds, it casts greater light on how his unique perspective and informs his writing.

That's what makes this volume such an informative, fascinating read, and what paints Simon as irreplaceable. How many critics would dare tip the sacred cow of Arthur Miller? In reviewing multiple productions of Death of a Salesman, Simon details his reservations about the classic play's dramatic merits and authoritatively compares the Willy Lomans of George C. Scott, Dustin Hoffman, and Brian Dennehy to that of the role's creator, Lee J. Cobb.

Most entertainingly, he also goes after The New York Times, taking Ben Brantley to task for his review of Neil LaBute's bash: latterday plays and perceptively declaring in his own critique of Tony Kushner's Angels in America: Perestroika that Kushner "might have continued fiddling with it even longer, except that Frank Rich, an Angels enthusiast, is quitting his post as chief drama critic of the Times, and his successor is said to be an only lukewarm Angelist: hence the need to catch Rich before he leaves."

The book is something of a "no-frills" item; the reviews are organized by the decade in which they were published, in chronological order but with no indication of the specific date or where they appeared. (Simon has written for the Hudson Review, National Review, and other publications in addition to New York.) It should also be noted that only show titles are indexed. Still, this collection is essential to theater libraries and to the contemporary American theater itself.