DIED. PENELOPE GILLIATT, 61, writer and reviewer of films and books; following a long illness; in London. A writer of style and intelligence, Gilliatt achieved stature in several genres. Her 1965 novel One by One became the basis of her screenplay for the 1971 film Sunday Bloody Sunday, for which she received an Academy Award nomination. The somber tale of a hetero- and homosexual love triangle was one of the very first popular works to treat such a subject unflinchingly. Gilliatt was also one of America's best-known film critics, writing reviews for the New Yorker from 1967 until 1979. She may have seemed more restrained than her emphatic colleague Pauline Kael, with whom she alternated reviewing duties in six-month shifts, but she possessed a slyly caustic wit ("There are no Negroes in this vision of the American space program," she wrote of Stanley Kubrick's 2001, "conversation with Russians is brittle with mannerly terror and the Chinese can still be dealt with only by pretending they're not there.") She stopped reviewing regularly in 1979, after novelist Graham Greene questioned the veracity of a story she wrote about him, and the author of another piece on Greene claimed Gilliatt had used his material without attribution.