Samuel —, author of stage plays Not I and Breath (7)
I believe the answer is:
beckett
(Other definitions for beckett that I've seen before include "Samuel -, twentieth century Irish playwright" , "Samuel . . . . . . ., author of ''Waiting for Godot''" , "Samuel --, 20th century avant-garde playwright" , "Samuel ---, dramatist (Waiting for Godot)" , "Samuel --, Irish dramatist" .)