Art experts have disagreed about whether art markets accurately reflect artistic importance. This paper uses published surveys of art history to construct a critical ranking of the 30 most important American painters of the last century, then uses auction records to identify the most expensive paintings by these artists. The results show a strong positive association between critical rankings and auction prices: there is a high rank correlation between the critical ranking of artists and a ranking of the artists by their single highest auction price, and the top artists in the critical ranking are highly disproportionately represented among auction sales over $10 million, $30 million, and $50 million. Auction markets do recognize artistic importance: the greatest artists produce the most expensive paintings, and it is their most important works that sell for the highest prices.