How many letters does the top answer for “author of the space merchants” have?

The most common answer is kornbluth (9 letters).

Crossword clue: author of the space merchants

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

kornbluth 9 letters wd-fact-v3

pohl 4 letters wd-fact-v3

author of 2001: a space odyssey 50% similar → clarke, kubrick

author of the space trilogy 50% similar → lewis

wrote the space merchants 50% similar → kornbluth, pohl