EVER SINCE Philip Roth introduced the neurotic, oversexed William Portnoy to the literary world, a band of literateurs has harried him. Reviewers accustomed to propriety panned the book and accused Roth of writing pornography. Zionists and orthodox Jews charged him with betraying his heritage and making a mockery of the Holocaust. Jewish mothers, appalled by what they perceived as scathing anti-Semitism, threatened to lace his chicken soup with arsenic.

Not surprisingly, this stream of hostility took its toll. The biting self-confidence of Roth's early prose-seems to have yielded to a tone of resignation and uncertainty.

Four years ago Roth unveiled The Ghost Writer--the first of a trilogy exploring the psyche and libido of Nathan Zuckerman. He followed it two years later with the second volume. Zuckerman Unbound. Now in The Anatomy Lesson--the new, final member of the series--Roth and Zuckerman seem to have resolved little.

The lead character is in many ways a proxy for Roth himself. A neurotic Jewish writer, Zuckerman is plagued by the tensions of his past and his career and seeks through sex, analysis and literature the missing element in his life.

The Anatomy Lesson lambastes modern culture with the same venom and guilt as its predecessors, and Zuckerman continues to be tormented by the same medusa-like females, self-righteous Jews, and spiteful relatives that have historically oppressed him. Yet if the subjects of The Anatomy Lesson sound all too predictable, the tone of the novel is distinct.

Zuckerman's desire to embrace humanity and combat stultifying forces continues to provide him with a source of artistic inspiration. He spends most of his time attacking the self-righteous hypocrisy of his foes, with much of the impetus for this feeling of inadequacy-and likely Roth's own self doubt-stemming from a welcome maturity in both character and author. Where once Roth's protagonists enjoyed a vicarious thrill while rebelling against religious and social mores, the rebellion seems to have lost much of its childish force:

I'm sick of raiding my memory and feeding on the past...I want an active connection to myself. I'm sick of channeling everything in to writing. I want the real thing, the thing in the raw, and not for the writing but for itself.

The all to vivid similarities between author and protagonist often make it difficult to separate the fictitious from the actual. When Zuckerman's hated critic, Milton Appel, accuses him of capitalizing on the ethnic eccentricities of Teaneck, N.J. and the lower East side, we cannot help but think of Roth's own battles with critics and his New Jersey origins.

But if such knowledge arouses sympathy for both character and author, it functions as a double-edged sword. While many of Zuckerman's responses seem noble in principle, his actions frequently assume a spiteful and egocentric quality. Instead of rising above the pettiness of his opposition, Zuckerman repeatedly stoops to their level. Constantly we are reminded of the emotional and physical suffering he has been forced to endure to the point of fanatic obsession.

Sooner or later there comes to every writer the two-thousand, three-thousand, five-thousand word lashing that doesn't just sting for the regulation seventy-two hours but rankles all his life. Zuckerman now had his: to reassure in his quotable storehouse till he died, the unkindest review of all, embedded indelibly (and just about as useful) as "Abou Ben Adhem" and "Annabel Lee," the first two poems he'd had to memorize for a high-school English class."

Nevertheless, much of The Anatomy Lesson is filled with witty dialogue and incisive reflections on human nature. Roth's of the constraints of both Jewish and Western culture--if overworked--are sharp and poignant. Perhaps more impressive is Roth's ability to elevate the commonplace into something almost sacred:

I legitimize feelings in people as really as anybody else. They need it dirty to get turned on? So what? They're still human beings, you know, and there are millions of them out there. All the men's magazines taken together have thirty million readers. That's more people than voted for George McGovern.

Such passages are needlessly crude, but they illustrate a depth and sensitivity to human possibility that few artists are able to so vividly capture.

Zuckerman's desire to return to medical school point. The clever blend of comedy and wit combined with a climactic tragicomic graveyard scene--where Zuckerman unsuccessfully tries to come to terms with himself--in many ways make The Anatomy Lesson triumph over Roth's previous works.

In many respects, the book represents a maturation of Roth's artistic vision. The self-deprecating Jewish humor provides a comic yet despairing perspective and enables Roth to hammer home his points more powerfully. Yet the extremity of this critical introspective and the vindictive nature of such criticism can make both Zuckerman and Roth seem like the very Jewish martyrs they revel in ridiculing. After all, Zuckerman's backaches are only just so interesting.