Analyses of Sirk's work, with their emphases on aspects of Sirk's formerly-criticized style, revealed an oblique criticism of American society hidden beneath a banal facade of plotting conventional for the era - Sirk's films were now seen as masterpieces of irony. The criticism of the 1970s and early 1980s was dominated by an ideological take on Sirk's work, gradually changing from Marxist-inspired visions in the early 1970s, to a focus on gender and sexuality in the late 1970s and early 1980s. Film critic Roger Ebert has said, "To appreciate a film like "Written on the Wind" probably takes more sophistication to understand than one of Ingmar Bergman's masterpieces, because Bergman's themes are visible and underlined, while with Sirk the style conceals the message."