Brecht would remain a prominent member of Fluxus until Maciunas' death, 1978. His work was included in each of the major "Festum Fluxorum" performances in Europe, 1962–63; in "Fluxus 1", 1963, the first "Flux Yearbook"; as part of the various "Fluxkits", collecting works by the group together; and was a key part of Flux performances and objects right up to the "Flux Harpsichord Concert", 1976 and the last "Flux Cabinets". An indication of his importance within the group is captured in a letter from Maciunas to Emmett Williams, April 1963, concerning plans Maciunas had been formulating with the marxist intellectual Henry Flynt;