She is of Hungarian background and attributes a childhood spent in the culturally diverse Queens borough of New York City as a significant influence on her writing career. Illes explains that her interest in divination began while playing with a Tarot deck at the age of six. Her first Tarot deck was the Builders of the Adytum (BOTA) deck, which she described in a 2005 interview as "formidable and very esoteric," an unusual starter for a child of her age.
She has a Bachelor of Arts in English and Communications from Rutgers College and earned a Graduate Certificate in Aromatherapy from the American College of Healthcare Sciences (previously known as the Australasian College of Health Sciences) in 1999.
Illes worked as a "telephone psychic" for Psychic Friends Network from 1991 to 1993. She went on to become a prolific author of reference books and contributed magazine articles in the ancient non-traditional arts.
Her writing interests include folklore, folkways, mythology, astrology, spellcasting, spirit-working, herbalism and traditional healing. She also covers the subjects of the occult, magic, divination, spiritualism, fairies, witchcraft and the paranormal.
A certified aromatherapy consultant, she has taught introductory courses on the subject at the Australasian College (2000–2002), and practices taromancy.
She sometimes holds workshops relating to her books or other specialized subjects. In 2012, she gave a workshop on the use of symbols as part of the SIgils & Signs Art Show at Observatory in Brooklyn. She gives similar workshops and presentations intermittently throughout the year.
The first complete book Illes wrote was about traditional methods of enhancing fertility. It contained a chapter about magic spells, which a publisher asked her to expand into a book of its own, eventually published as Pure Magic: A Complete Course in Spellcasting. The manuscript about fertility was set aside, but in a 2011 interview by The Witches' Almanac, Illes mentioned that she may eventually publish it under the title, Frogs and Pomegranates.
After the release of The Encyclopedia of 5000 Spells, her publisher suggested an encyclopedia about witchcraft. A note of encouragement from the Non-Wiccan Witches Yahoo group persuaded her to accept the challenge, which led to The Element Encyclopedia of Witchcraft. According to Illes, most encyclopedias about witchcraft were written by outsiders and "not really about witches or their craft."
Her last name, Illes, is pronounced as you would with the "Ph" omitted from "Phyllis." Judith Illes was used as the byline for some of her Tour Egypt articles, rather than her Hungarian name, Judika.
In an interview with The Witches' Almanac, Illes disclosed that she used "Judith Joyce" as her byline when she wrote The Weiser Field Guide to the Paranormal due to the short period between her other Weiser field guides.
- The Encyclopedia of Mystics, Saints & Sages: A Guide to Asking for Protection, Wealth, Happiness, and Everything Else!. Harper Collins Publishers (2011). ISBN 978-0-06-200957-9.
- The Weiser Field Guide to the Paranormal. Red Wheel/Weiser LLC (2010). ISBN 978-1-57863-488-0. (published under the pseudonym, Judith Joyce)
- The Weiser Field Guide to Witches: from Hexes to Hermione Granger, From Salem to the Land of Oz. Weiser Books (2010). ISBN 978-1-57863-479-8.
- The Encyclopedia of Spirits: the ultimate guide to the magic of fairies, genies, demons, ghosts, gods, and goddesses. Harper Collins Publishers (2009). ISBN 978-0-06-135024-5.
- The Encyclopedia of 5000 Spells. HarperOne (2008). ISBN 978-0-06-171123-7. Previously published as The Element encyclopedia of 5000 spells: the ultimate reference book for the magical arts. HarperElement (2003). ISBN 0-00-716465-3.
- Magic When You Need It: 150 Spells You Can't Live Without. Weiser Books (2008). ISBN 1-57863-419-9. Previously published as Emergency Magic! 150 Spells for Surviving the Worst Case Scenario. Weiser Books (2002).
- Pure Magic: A Complete Course in Spellcasting. Red Wheel/Weiser LLC (2007). ISBN 1-57863-391-5 and ISBN 978-1-57863-391-3 . Previously published as Earth Mother Magic: Ancient Spells for Modern Belles. Fair Winds Press (2001). ISBN 1-931412-65-0.
- The Element Encyclopedia of Witchcraft: a complete A-Z of the entire magical world. Harper Element (2005). ISBN 0-00-719293-2.
The following articles by Judika Illes were part of her monthly column, Beauty Secrets of the Ancient Egyptians, published during 2000 and 2001 by the Egyptian Ministry of Tourism in its on-line magazine, Tour Egypt.
Ancient Beauty Secrets (monthly column series):
- Ancient Facial Secrets (Introduction), Vol. I, No. 1, June 1, 2000.
- Haircare and Wigs, Vol. I, No. 2, July 1, 2000.
- Perfumes of Ancient Egypt, Vol I No. 3, August 1, 2000.
- Ancient Egyptian Eye Makeup, Vol. I, No. 4, September 1, 2000.
- Nefertem, Ancient Lord of Perfume, Vol. I, No. 5, October 1, 2000.
- Tattoos in Ancient Egypt, Vol. I, No. 6, December 1, 2000.
- Henna, Vol. II, No. 1, January 1, 2001.
- Fertility Shrines of Ancient Egypt, Vol. II, No. 2, February 1, 2001.
- Tutankhamun's Perfume, Vol. II, No. 3, March 1, 2001.
- Flowers: The Fundamental Fashion Accessory, Vol. II, No. 4, April 1, 2001.
- The Beginning of the Book of Making an Old Man into a Young Man..., Vol. II, No. 5, May 1, 2001.
- Cats Eyes and Eye Make Up, Vol. II, No. 7, July 1, 2001.
- Glass Beads: "Fabulous Fakes" and the Birth of Costume Jewelry, Vol. II, No. 8, August 1, 2001.
Feature Articles published in Tour Egypt, 2000 - 2001:
- Facing North, April 2009
- The Witches' Almanac. The Witches' Almanac, Ltd. August 2011. pp. 82–84. ISBN 978-0-9824323-6-5.
- TWPT Talks to Judika Illes TWPT (2005). Retrieved 2010-1-27
- Joy and Fascination: An Interview with Judika Illes Facing North (April 5, 2009). Retrieved 2010-1-27
- Department of Aromatherapy Description of certificate program, retrieved 2010-1-25
- Tour Egypt Archives: Ancient Beauty Secrets Retrieved 2010-1-25
- Judika Illes. Hathor, Lady of Beauty Tour Egypt. Egyptian Ministry of Tourism. retrieved 2010-1-26
- Judika Illes. Beauty Salts Tour Egypt. Egyptian Ministry of Tourism. retrieved 2010-1-26