great thread, lot’s of people are clearly into books 
On the ORCID angle @omg.jacky.wtf raised: that already runs in Sifa ID today (example: Juan A. Esteban (@juanesteban.art) | Sifa ). Sifa pulls someone’s ORCID publications (once connected) and their standard.site ones and surfaces them on their professional profile, no manual entry. Also works with non-atrproto things like your Github activity and/or RSS items if you add and verify them.
The link from a record to a person doesn’t run through a DID though. Of course a Sifa user has one by definition (that’s the account itself), but the match rides on a shared external identifier: the source record carries something structured and stable like ORCID, the same ORCID sits on the profile, and Sifa just joins based on that. The record itself doesn’t have to carry a DID.
Same trick would work for books, AFAIK: if contributor records carry a structured author identifier (ORCID, ISNI, VIAF, an OpenLibrary author key, Wikidata), a profile app like Sifa could already surface someone’s books on their profile by identifier match (assuming the user adds/links the ID to their atproto account of course, no magic here 
). But yeah: no DID needed, works perfectly.
The above mentioned claims-vs-edit-rights split: an author claim record keyed to a DID (or ORCID) is pretty much what lets a profile app auto-pull and pre-fill an author’s own books once they join atproto? Direct backlink discovery via Constellation.
On the claiming itself: the calendar/speaker thread is going towards the same idea where a self-written claim record is pointing at the subject, the counterparty writes their own half, the appview derives the confirmed state. Cartridge already does the claim/verify side today as well (but manually verifying the game companies claiming the games and then pulling it into the claimers PDS). “Author claims their book” looks like the same shape as “speaker claims their talk” or “game company/artist claims their game” to me.
For Sifa nothing new needed to make the books work, just happy to start (automagically) adding authors books to their Sifa profiles once this has been setup