A developer's quest to build a GoodReads alternative reveals a fundamental problem with book metadata: ISBNs. While platforms like Letterboxd thrive on The Movie Database, creating a similar book-focused service faces a unique challenge. The Movie Database powers Letterboxd with clean, canonical film data, but no equivalent exists for books.

When searching for "The Last Unicorn" using the Google Books API, developers encounter multiple entries for the same work - each format and edition has its own ISBN. This creates a mess for search functions, as users want to log "The Last Unicorn" not select from dozens of versions. The FRBR model distinguishes between works, expressions, manifestations, and items, but most book APIs return manifestations instead of the abstract works users actually want to track.

OpenLibrary offers cleaner data with its work-based approach, but even it struggles with duplicates and incomplete metadata. With over 40 million works in its catalog compared to The Movie Database's million films, the book problem is an order of magnitude harder. The developer notes that GoodReads' clunky interface likely stems from being "a low-priority offshoot of Amazon's book-selling business." Despite these challenges, the author plans to continue exploring solutions for a better book-tracking platform.