family register book; family registry archive
Refers to the official bound volume or archive where family registers (戸籍) are kept, typically at a municipal office. Not the individual certificate (戸籍謄本/抄本) but the master record book.
You need to apply to view the family register book at the city hall.
Old family register books are kept at the Legal Affairs Bureau.
戸籍謄本 is a certified copy of an individual family register, whereas 戸籍簿 is the master record book.
Compound of 戸籍 (family register) and 簿 (record book, register).