There are rules you're supposed to follow when you make a documentary.

Bart Layton just happens to think they're ridiculous.

"There's this idea of documentary purity that is not terribly realistic," says the British director, whose debut feature, "The Imposter," sails into limited release this weekend on the strength of a 96% Rotten Tomatoes rating (at press time). "I think everyone who's ever picked up a camera or sat in an edit suite will be aware that there are lots of subjective decisions being made. This idea that you can create a film that is purely objective, it's just not a realistic ideology."

Layton's film tells the stranger-than-fiction story of Frédéric Bourdin, a charming young congenital liar who in 1997 persuaded authorities on two continents that he was Nicholas Barclay, a Texas boy who had gone missing three years earlier at age 13. Somehow, even Barclay's family fell for his act, taking him...