1To write and publish (a book, article, etc.). A formal/literary term often used for authorship or academic publication.
その教授は多数の論文を著している。
That professor has authored many papers.
彼女は旅行記を一冊著したあと、テレビにも出演した。
After she wrote and published a travelogue, she also appeared on TV.
著すは書くより堅い表現で、公式文書や紹介文などで使われる。
'著す' is a stiffer/formal expression than '書く', used in official documents and introductions.