In Nov 02 there was a Radio 4 programme on Outsider Art.
Colin Rhodes has written a book on the subject, published by Thames and Hudson.
Outsider artists are unprejudiced by the conventions of the professional art world.
Many Outsider Artists don't even think of themselves as artists.
There is clearly an overlap between Outsider Art and Naive Art.
Outsider Artists are Amateurs; they produce art through love or necessity.
The most celebrated Outsider Artist seems to be Adolf Wolfli, who spent most of his life as a psychiatric patient.
Co-founder of the Stuckists, Billy Childish, does not regard himself as an Outsider.