Refers to a professional librarian, often with a qualification. Used in contexts like school, public, or specialized libraries.
彼女は学校の司書として働いています。
She works as a school librarian.
She graduated from university and became a librarian.
司書の資格を取るために勉強中です。
I'm studying to get a librarian's qualification.
He is studying to obtain a librarian's qualification.
She works as a librarian at the city library.
史書 (also read ししょ) means 'history book,' a completely different meaning from 司書 despite sharing the exact same pronunciation.
秘書 (secretary) looks and sounds similar to 司書 (librarian) but refers to a completely different profession.
司書 is counted with 人, the general counter for people.
Compound of 司 (manage, administer) and 書 (book, document). The term was coined in the modern era to denote a professional librarian.