A somewhat formal term for a person who writes books or articles, often used in literary or professional contexts.
He is a famous author.
その著作家は新しい小説を発表した。
The writer published a new novel.
著述家 is a near-synonym also meaning 'writer' or 'author', but 著作家 is slightly more common and may be preferred in everyday formal contexts.
Compound of 著作 (chosaku, 'writing' or 'authorship') and 家 (ka, 'person' or 'specialist').