Urim VeTummim - Prophetic Stones atop the Head Kohen's Breastplate

Prophecy

Procedure for Asking Questions: Yoma 73a-b

Method of Answering Questions: Yoma 73b

Actual Occasions of Use: Yoma 73b

Asking questions of law: Eruvin 45a

Asking regarding a decision to go to war: Eruvin 45a