Kirjathsepher means “city of books.” It was another name for Debir, a Canaanite city associated with Judah.
Kirjath-sepher appears in the account of its capture by Othniel after Caleb offered his daughter to the conqueror. It is named in Joshua and Judges.
The supplied material provides no additional background beyond its identification with Debir and its meaning, “city of books.”