Sefer Yetzirah, dated variously between the 2nd and 9th centuries, teaches creation through the ten sefirot (numbers/depths) and the twenty-two Hebrew letters, divided into mothers, doubles, and simples, mapped to elements, planets, and signs. Every later Kabbalist, and every Golden Dawn correspondence table, builds on its scheme.
The famous application: medieval legends credit the book with the recipe for the golem, letters animated into a servant. Prague's rabbi Loew got the famous version; the Yetzirah connection is the tradition's own claim, not the text's instruction manual.
The anachronism that keeps landing: the book describes reality as generated by a symbol set combined under rules, information as the substrate of matter. Modern physicists speak of information-theoretic universes; the Yetzirah got the grammar first and the mystics got the syntax.
If letters can build a world, what is the world built from, and who holds the pen now?