ALMOST 20 years ago, John Howard Griffin, a white novelist and historian, became black. Through a series of medical treatments, Griffin changed his skin color, traveled through the Deep South as a "black man" for several weeks, and later chronicled that experience in the 1961 best-seller "Black Like Me."

The book opened a window to the wider public on the Southern system of racial interaction and changed Griffin's life forever.

Now 57 and living in Fort Worth Tex., Griffin recalled in a telephone interview earlier this week what he had hoped to do in the book and whether there have been substantial changes in racial relations since the 1960s.

"What I was trying to do was to destroy the communication barriers between blacks and whites, to show the oppressor what happens when he oppressed," said Griffin. "I wouldn't begin to be able to establish what my book did in that regard, though."

What Griffin does see, however, is not a bettering of relations between the races, but "the illusion of a lot more progress. Situations like the Bakke (Allan Bakke "reverse discrimination" case) case are very distressing and fearful because it seems to me the beginning of another regression in racial understanding."

While the book is still being published and is frequently required reading in schools (Griffin recently added an epilogue to the new edition appending the events of the 1960s), it changed Griffin's life as a novelist into that of a proselytizer for better racial understanding.

"I thought of myself as a novelist," said Griffin, who had published two novels, the bestselling "The Devil Rides Outside" and "Nunni" prior to "Black Like Me." "I'd never thought of myself as having a vocation to bring an understanding between the races. But I spent all those years of the 1960s fluctuating back and forth between black and white worlds."

Griffin became a consultant on inner city disturbances during the time when the cities were erupting into flames and racial polarization. He expanded his interest to include other minorities: Native Americans; the elderly poor; and Pakistanis in Canada.

Griffin's life has had strange quirks and odd twists. Originally, he'd planned to be a psychiatrist but his career was interrupted by blindness from a World War 11 accident. He bacame a novelist instead, remaining blind for 10 years before he miraculously regained his eyesight.

He cites his sightless days as part of the impetus for his book and his involvement in interracial relations.

"Being blind was a great learning experience," he said.

"As a Southerner, all the stereotypes I'd been brought up with, the speech patterns that blacks were supposed to have, the appearance, all those delusions had to go out the door."

Even though his life has been slowed down in the last year because of a heart attack, Griffin, who lives with his wife and four children, still keeps a full schedule. He is currently working on another novel and a biography of Trappist monk Thomas Merton.

"Oh, I have four or five calls for interviews everyday," he said merrily. "And in about 30 minutes, Studs Terkel is coming by to do a taped interview."