How many letters does the top answer for “author of the cotton club” have?

The most common answer is cage (4 letters).

Crossword clue: author of the cotton club

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

cage 4 letters wd-fact-v3

an enclosure made or wire or metal bars in which birds or animals can be kept

coppola 7 letters wd-fact-v3

United States filmmaker (born in 1939)

author of fight club 50% similar → palahniuk

author of the club dumas 50% similar → perezreverte

home of cotton club 50% similar → manhattan

wrote the cotton club 50% similar → cage, coppola