Robert Warshow, who died in 1955, was probably the best American critic of popular culture of his time. After his death his essays were collected in a single volume entitled The Immediate Experience: Movies, Comics, Theatre and Other Aspects of Popular Culture.
Harvard University Press recently published an enlarged edition of the book. It includes all the original material, eight previously uncollected essays by Warshow, and pieces by David Denby and Stanley Cavell that discuss Warshow's legacy.
I wrote a review of the new edition for Other Voices.