She'elat Chalom — the Dream Questionשאלת חלום

Incubated dreaming: purify, formulate a single question, recite the appointed verses and names at the threshold of sleep, and receive the answer in a dream — a technique attested from Geonic responsa through the Ashkenazi Pietists (whole manuals survive) to Chaim Vital's diary, which uses it like correspondence. The moon-sphere of Yesod, treasury of images, consulted as an oracle with office hours at night.