Kit was reunited with the famous golden hare during filming for the programme
In 1979, Gloucestershire artist Kit Williams turned Britain into a giant treasure map, promising a golden hare, buried in the earth, to the first person who solved the riddle of his book Masquerade.
The hysteria that followed the hunt drove Williams underground to his studio near Stroud, where he has continued to create complex and beautiful art, which he refuses to publicly exhibit.
Kit is also the man behind several Gloucestershire public works of art - namely The Dragonfly Maze in Bourton-on-the-Water, The Wishing Fish Clock in Cheltenham's Regent Arcade, and the Lady and Tiger Illusion Clock which used to be on display in the town's Beechwood Shopping Centre.
Now, in his first interview in two decades, Kit lifts the lid on life before and after Masquerade.
In a documentary shown on BBC Four on Wednesday 2 December 2009 he revealed why he walked away from the media spotlight and discussed the creation of the book 30 years ago.
Kit explains why he decided to write the book: "I thought what I must do is find a way to make people to look and look again.
"And if I said 'You must really look at it because this is art', that would turn people off.
"But if I said there's some sort of puzzle here which you must work out they would be looking at art through the back door."
In the time Kit has been away from the limelight he has painted more than 300 pictures, none of which have ever been put on public display.
Kit describes the creative process: "A painting can take up to 800 hours and by the time I'm four months into it I really get fed up with it, but then I turn a corner and it starts all coming together and it's just wonderfully satisfying.
"I need a quietness because it's as if my ideas are very delicate shoots that come up from the ground and I have to nurture them.
"If there was all that business about having to do media things and have media friends and so on, and go to parties, that noise would be too much and I would never hear these little shoots coming through the ground.
"So I work more like a monk in a cell and just once a year show my work to people who I invite to come and see it."
'The Man Behind the Masquerade' will be shown on BBC Four on Wednesday 2 December 2009, 21:00 GMT, and will be available on the BBCiPlayer for seven days after broadcast.