Convict-author Jack Henry Abbott emerged briefly from prison today to plead not guilty to the charge of murdering a 22-year-old waiter July 18, at a time when his published letters from prison began to climb the national best-seller lists.

Under tight security, the 37-year-old author of "In the Belly of the Beast," a fearsome account of his 25 years in prison, was moved from the federal correctional facility here early today to the 11th floor of the Criminal Courts building for arraignment on the murder charge.

Abbott, whose gift for language has been praised by the critics, Norman Mailer and other literary figures, spoke only four words during the brief court session. His calm but grim demeanor contrasted sharply to his smiling appearance in a New Orleans federal court last month after his capture.

"Not guilty, your honor," Abbott replied to today's formal charges.

Abbott was indicted Wednesday for second-degree murder in the fatal stabbing of Richard Adan, an aspiring actor who waited tables at the Bini-Bon restaurant on Manhattan's Lower East Side. The stabbing occurred at 5:20 a.m., shortly after Abbott was seen arguing with the waiter over the availability of toilet facilities.

The crime coincided with one of Abbott's infrequent periods of freedom. He was living in a halfway house near the Bini-Bon, and was just a few days short of the parole that Mailer and other publishing figures had helped to secure.

Legal documents made public today revealed that Abbott admitted the stabbing to police after his Louisiana arrest on Sept. 26, but claimed it was "in self-defense."

After court, defense attorney Ivan Fisher explained his security precaution request: "I am afraid someone is going to kill him," because of disclosures in his book.