Mario Jiménez-Castillo was born in the city of Santa Ana, in El Salvador, in 1973. He has studied divination in different forms, including the meaning of dreams. Since he was a teenager he demonstrated a big interest in metaphysics, reincarnation, astrology, spirit communication and theology. He lives in California, and writes astrology and esoteric columns for some newspapers and internet sites. He gives spiritual counseling in English, Spanish and Portuguese.
Some of his books published by Llewellyn are Dictionary of Dreams (which has been several times on the bestselling list), Dictionary of Saints, and Magic of Fruits and Vegetables.