The sub-series is comprised of letters, postcards and greeting cards exchanged with peers (artists, writers, professors, humanists, publishers) of Beissel including: Angelika Arend, Werner Berchem, Werner Berg, Per Brask, Ronnie Brown, Anthony Cassils, Patrick Drysdale, Leo Enright, Heide Fruth-Sachs, Keith Garebian, Gary Geddes, Albert-Reiner Glaap, Amanda Hale, Jack Herbert, Jürgen Jankofsky, Anne Kulling, Renée Makino, Helmut Markus, Rob McLennan, Najwa Nasr, Anja Oppermann, Bruno Petrenko, Andrew Proctor, Uta Regoli, Walter Riedell, Gillian Rimington, Gerd Rohmann, Fruma Rothberg Sanders, Desmond Scott, John Smith, Richard Thain, Axel Vieregg and Norman Yates, to name a few.
There is also an extended correspondence with Edward Lacey, Walter Bauer and Wolfgang Bottenberg, the latter including a musical score for 'The World Is a Rainbow'.