Refers to a person who writes a specific piece, such as an article, book, or report. Often used in formal or professional contexts.
The author of this book is a famous scholar.
We are looking for contributors to the magazine.
執筆者 emphasizes the act of writing a specific piece (like a report or chapter), while 著者 focuses on ownership/authorship of the finished work.
Compound of 執筆 (writing) and 者 (person). The exact historical derivation is uncertain, but the components clearly indicate 'one who writes'.