By Kevin Connolly
BBC News, Washington
Griffin exposed the discrimination prevalent in the Deep South
How much does the colour of our skin make us who we are, and shape the way the world sees us?
The answer to that question may seem obvious now after decades of slow and uneven progress towards racial equality and enlightenment.
It would have seemed very different 50 years ago to the white Texan writer John Howard Griffin, when he embarked on one of the most remarkable one-man social and psychological experiments in history.
Griffin was the white man who fooled hundreds of Americans into believing he was a black man as he travelled through Louisiana, Mississippi, Alabama and Georgia - and who felt at first hand the bigotry that meant.
In later life, the six-week venture - described in his book Black Like Me - was to expose him to the hatred and violence that underpinned that bigotry, too.
When he toured the South lecturing to white audiences about his experiences as a black man, he was threatened, intimidated and, on at least one occasion, seriously beaten.
In the American Deep South in 1959, to be black was to be despised - to be treated as something less than human.
There was the grinding poverty, of course, and the segregation and legalised discrimination which reserved certain railroad cars, bus seats and drinking fountains for the whites.
But there were humiliations that ran deeper still. In some states, black men accused of looking at white women with lust in their hearts could be arrested under laws which made "ogling" a form of sexual assault.
In others, "eyeballing" laws meant that failing to look down at the sidewalk when white folks passed by could lead to a charge of behaving in a confrontational way.
As part of his research, Griffin worked as a 'shoe shine boy'
Black performers - if they were ever hired by Southern theatres - were reminded in their contracts not to look at white women in the audiences.
John Howard Griffin was a remarkable man. As a Texan teenager who found himself in France at the outbreak of World War II, he helped to smuggle Jewish children to safety and freedom.
He then served with distinction in the US Air Force in the Pacific. And then, after the war - when illness struck him blind for 10 years while he was still relatively young - he became a prolific writer.
It was after his sight returned that he hit upon the idea of Black Like Me, the work which is his most important legacy.
The whole business of racial impersonation might make us feel vaguely uncomfortable now, but in 1959 a black writer simply could not have found an audience for such a graphic portrayal of African-American grievance.
Only a white writer prepared to take the extraordinary steps that Griffin took could tell the story.
His biographer Robert Bonazzi - who went on to marry Griffin's widow - told me how in practical terms the white Texan set up transforming himself into a black Southerner.
"He took a drug called Oxsoralen, which is to combat vitiligo.
"In other words, black people if they get white splotches on their skin they would take this medicine to cover the white splotches. And he was told by a dermatologist that if he took massive doses of this and got under an ultra violet sunlamp - which he did - he would turn quite brown, which he did."
Griffin's grim adventures as a black man in a white man's world are worth reading. They remain a set text for many American high school children.
The work raises all sorts of interesting questions, not just about life in the states of the old confederacy nearly 100 years after the American Civil War, but also about race and identity.
After all, if Griffin could fool white people to the extent that they were prepared to mistreat him, then it is fair to conclude that the colour of our skin does not have much to do with the content of our character.
Griffin's experiment probably stands alone in history as a benign example of racial impersonation - but by a curious coincidence, exactly 50 years on we see a couple of examples of the darker form of the tradition which remind you that progress towards that age of racial enlightenment is still very uneven indeed.
First, French Vogue published a photograph of a white model painted black - raising the rather obvious question of why they did not simply use a model with black skin.
I suspect you will wait rather a long time to see Vogue using pictures of someone with another natural skin tone painted white.
And then, on a talent show in Australia, a group of men did an "impression" of the Jackson Five in black make-up, or blackface, that would not have been out of place in an Alabama minstrel show in the 1890s.
Interestingly, the American entertainer Harry Connick Jr was there as a guest judge and was thus able to explain to the Australian audience what the performance looked like to other eyes.
The author passed unnoticed in the black neighbourhoods of New Orleans
He said simply: "I know it was done humorously but we've spent so much time trying to not make black people look like buffoons that when we see something like that we take it really to heart and I know it was in good fun but if I had known it was going to be part of the show I probably, I definitely wouldn't have done it."
It may seem strange to be marking Black History month (which in the UK, unlike in the US and Canada, is celebrated in October) by reporting breaches against good taste that seem to belong to another age.
It is 31 years since the BBC stopped broadcasting its own contribution to this unhappy genre - the Black and White Minstrel Show.
I asked Hilary Shelton of the National Association for the Advancement of Colored People to put into words what he must have hoped would be obvious by now.
He told me: "These tools were used in the past to dehumanise. In the US and Great Britain we share common experiences with race relations that make us a bit more sensitive to what it means to put someone in blackface, to put a caricature wig of an African-American on one's head, to exaggerate the size of one's lips or the size of one's nose."
Blackface was for years a staple of mainstream entertainment rooted in the minstrel shows of 19th-Century America.
Big stars like Bing Crosby and Judy Garland have appeared in blackface and one of the biggest of them all, Al Jolson, rarely appeared without it.
More highbrow examples of the "art" - Laurence Olivier playing Othello for example - seem to me to raise subtly different questions which are certainly worth exploring, although perhaps not within the confines of this article.
It is, by now, forgotten more or less (unless you buy French Vogue or watch Australian talent shows, of course) so it is a little depressing to find it cropping up in Black History Month and on the anniversary of John Howard Griffin's challenging odyssey through Old Dixie.
At least it serves a purpose though - it reminds us that Griffin's experiment was perhaps the only occasion on which one man assumed the race of another with noble intent.
It is worth reading what he wrote - and then reflecting, in this age of the first African-American president, on how far we have come.
And how far we have to go.
Photos by Don Rutledge from Black Like Me by John Howard Griffin, published by Souvenir Press