THE WILLFUL grotesqueness of Frederico Fellini's films - the deformed bodies, daffy ingenues, bloated pederasts, madeover harpies, male nymphs - apparently spills over into his private life. In this highly impressionistic and contemplative biography, Liliana Betti guides us through Fellini's daily routine, a menagerie of the fantastic.

We are introduced to Fellini's masseur, a short, thick-set deaf ex-boxer, who works out regularly, gasping and sweating, for his employer's amusement. Fellini's mail is opened for us. The communication falls into two categories: people offering something (advice, their bodies, scripts something ("I need help," reads one letter, "I beg you, do not say no, but I need a wig..."). We are invited to a casting call with the "usuals": the man who accuses Fellini of being a Martian, the ex-hotel manager who pulls out his dentures to do impressions of old men in westerns, the hermetic deaf poetess who has a metal knee and cannot sit down.

It is not surprising to learn that Liliana Betti met Fellini in 1962 after writing him a series of bizarre letters, which resulted in her joing Fellini's camp as press aide, assistant director and chauffeur. She soon found that the only ones who pique Fellini's curiosity, and with whom he corresponds punctually, are the most outrageous. He has, seemingly, an unlimited threshold for the extraordinary, and his films in recent years - Fellini Satyricon, Fellini's Roma, Fellini's Casanova - are testaments to that point. No longer do his pictures have the superb balance and subtle rhythms of his early films, I Vitelloni, La Strada, and Nights of Cabiria, nor the satirical edge of his transitional films, 8 1/2 and La Dolce Vita. He has grown into a showman, a complacent clown, delighting in his own extravagance, celebrating excess, chaos, the apocalypse. Despite the striking visual sense and erotic suggestiveness of his later work, he has not put together a film of coherence and vision, with the exception of Amarcord, in well over a decade.

It is these years of phantasmagoria Betti covers. She does not provide even the barest bones of career information or biographical data. (Giulietta Masina, Fellini's wife for over 35 years and star of several of his pictures, is almost completely ignored.) Betti instead settles for a series of anecdotes and analytic disgressions designed to illustrate story continuing just continuing the article. and explain Fellini's various personality tics. The result is intimate, even daring, in its insistence in delving into the director's psychology.

However ingenious Betti is in seeming indiscreet, several major omissions lead one to believe otherwise. She discusses Fellini's personal habits for the most part abstractly and philosophically, avoiding specific examples of temperament. In a chapter devoted entirely to Fellini's penchant for not telling the truth, she gives not a single example. She hints at his sometimes cruel behavior toward actors, teasing the reader with stories of discord on the set ("a brawl, a fistfight, a gunshot") but, again, fails to develop any episode which might smack of real unpleasantness.

Betti's writing also gravitates toward the metaphysical with the same rampant overintellectualism Fellini chided her for back in her letter-writing days. Even a hapless egg custard at the director's favorite restaurant takes on the weightiness of "a meditation, a Shakespearean soliloquy, a Pythagorean theorem." In discussing Fellini's relationship with the character Casanova in the finished film, she writes: "It seemed as if Fellini and the film's personage could not coincide either by abandoning identity or according to the rules of identification. They only succeeded in mingling together, contaminating each other, wallowing hysterically in a zone that was heavy with inconclusive impulses."

Some heavy zone.

Yet there are some unexpected nuggets unearthed here - witty anecdotes one won't find in more exacting and polished studies of the director: Fellini visiting a mental institution in "quest of emotions"; Ingmar Bergman arguing in a tizzy of one-upmanship about who really had been closer to death; producer Dino De Laurentiis pleading with Fellini to consider Robert Redford as his Casanova. On the latter occasion, the incorrigible De Laurentiis urges, "Why can't you take Redford? Listen, Fefe, he'll follow you like a puppy dog. "Redford, fetch! Redford sit! "" It is in moments like these one wants Betti to ditch the analytic bull and get down to the real bull, the stuff "intimate portraits" are made of. CAPTION: Picture 1, Still from Fellini's "Satyricon"; Picture 2, Fellini (seated) at the set of "Juliet of the Spirits"; Picture 3, Anita Ekberg in the movie "La Doice Vita"