How many letters does the top answer for “a short introductory essay preceding the text of a book” have?

The most common answer is foreword (8 letters).

Crossword clue: a short introductory essay preceding the text of a book

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

foreword 8 letters wn-def

a short introductory essay preceding the text of a book

preface 7 letters wn-def

a short introductory essay preceding the text of a book