# PSBI v0.1 — Pan-African Sovereign Book Identifier (provisional)

The PSBI is a sovereign identifier for **one book edition, language and publication format**, including print, EPUB, PDF and audio formats. It is not an ISBN and does not claim ISO 2108 status or global supply-chain compatibility.

Structure: `B-CC-YYYY-NNNN-C` with the same country, year, four-character base-36 sequence and weighted mod-11 check-character algorithm defined in the PSSN specification. `B` creates a separate namespace. Identifiers are never recycled.

Each PSBI belongs to one permanent PAI record and may link to a parent intellectual work using `parent_uid`, plus associated ISBN(s) and external identifiers. The current implementation requires an `edition` and a `format` for book registrations. A new format or language edition must obtain its own record and sovereign book identifier, linked to the related work where appropriate.

The namespace, authority, metadata schema and preservation policy require governance ratification before asserting a published final standard. Other libraries and retailers may voluntarily use PSBI in their catalogues; they are not required to accept it.