Tanakh is an acronym — Torah (the five books), Nevi'im (prophets), Ketuvim (writings) — and the tiering matters: Torah has the highest authority, and the others are read through it. Jewish reading is inseparable from the oral tradition that interprets it, which is why the Karaite rejection of that tradition produced a genuinely different religion. The scroll itself is handwritten by a trained scribe on parchment, and a single wrong letter renders it unfit for use until repaired.