1) AKA Corno di Bassetto 2) Dramatic monogram 3) Famed literary monogram 4) Great playwright 5) Heartbreak House auth 6) Irish wit and playwright 7) Literary initials 8) Literary monogram 9) Major Barbara auth 10) Major Barbara monogram 11) Man and Superman monogram 12) Playwright, initially 13) Pygmalion inits Found on https://www.crosswordclues.com/clue/gbs