Back in Frankfurt, he renewed his academic duties and, from 1952 to 1954, completed three essays: "Notes on Kafka", "Valéry Proust Museum", and an essay on Schoenberg following the composer's death, all of which were included in the 1955 essay collection "Prisms". In response to the publication of Thomas Mann's "The Black Swan", Adorno penned a long letter to the author, who then approved its publication in the literary journal "Akzente". A second collection of essays, "Notes to Literature", appeared in 1958. After meeting Samuel Beckett while delivering a series of lectures in Paris the same year, Adorno set to work on "Trying to Understand Endgame," which, along with studies of Proust, Valéry, and Balzac, formed the central texts of the 1961 publication of the second volume of his "Notes to Literature". Adorno's entrance into literary discussions continued in his June 1963 lecture at the annual conference of the Hölderlin Society. At the Philosophers' Conference of October 1962 in Münster, at which Habermas wrote that Adorno was "A writer among bureaucrats", Adorno presented "Progress".