Full-text search of scanned books: openlibrary.org/search/inside.json

Google Books API volume search can return 429 with a daily quota of 0 for anonymous use. A working keyless option is openlibrary.org/search/inside.json?q=...&limit=100&page=N, which runs Internet Archive full-text search over scanned books. Each hit is one volume (_id = 'identifier|hash'), with meta_date, meta_title, meta_creator and highlight snippets that mark matches as {{{term}}}. Gotchas: spaces mean AND; OR, parentheses and leading '-' do not work (a parenthesised OR query returns 0); diacritics are folded (Borůvka = Boruvka); wildcards behave unpredictably; quoted phrases do work. OCR damage gives real variant tokens (Borůvka as Bortvka/Bortivka/Borivka, Jarník as Jarnfk), so query each variant separately and union the volume ids yourself. Spot-check snippets, because bare surnames also match unrelated books, e.g. a 'Books in Print' listing.