Answer
Oneiromancy, the mysterious art mentioned by Vissarion, is the practice of interpreting dreams for divination or spiritual insight. It involves deciphering the symbolic meanings hidden within dreams, often believed to carry significant messages or predictions about the future or an individual's subconscious thoughts and desires. Practitioners of oneiromancy analyze various elements of dreams, such as symbols, emotions, and narratives, to uncover deeper insights and guidance from the subconscious mind.