A good article from the New Yorker - Mystery Train: Martin Ramirez, outsider by Peter Schjedahl. An excerpt:
"Ramírez’s art is less rich in formal invention than Wölfli’s and in poetic resonance than Darger’s, but it is more stylistically resolved and emotionally concentrated. He has in common with them an extravagant giftedness. All would have been stars in any art school, had they attended one. That they eluded contact with institutions of fine art owes something to personal disarray and something to chance, in a ratio impossible to gauge. It’s a small thing, which makes them hard cases, exceptions proving the existence of a rule—that art, to be recognized as such, requires grounding in both individual biography and common culture. What can we do with and about the rush of pleasure and enchantment that the unlicensed genius of a Ramírez affords? I recommend taking it as a lesson in the limits of how we know what we think we know. Unable to regard such work as part of art’s history, we may still have it be part of our own."