How many letters does the top answer for “one who writes a monograph.” have?

The most common answer is monographist (12 letters).

Crossword clue: one who writes a monograph.

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

monographist 12 letters web-def

One who writes a monograph.

one who writes a treatise. 50% similar → treatiser

one who writes novels 50% similar → novelist

one who writes on heresies. 50% similar → heresiographer