Darby Costello was born in America and studied astrology in Boston in the 1960s. From there she went to Africa, where she worked with tribal healers and diviners. Now she lives in London where she teaches and writes books for the Centre for Psychological Astrology, founded by Liz Greene and Howard Sasportas in 1984. Her first book was The Astrological Moon.

Darby is a visiting tutor for the Faculty of Astrological Studies in London and The London School of Astrology. She teaches and lectures throughout Europe and occassionally other parts of the world. In 2006 she taught in Bali and in 2008 in America. In 2009 she taught in Bali again. In 2010 she will be teaching in Seattle, Washington; Fairbanks, Alaska and Santa Fe, New Mexico.

Darby has recently been awarded a Master's Degree in 'Cultural Astronomy and Astrology' by Bath Spa University. This has given her a greater taste for history and a deeper love of writing. However, her first love in astrology is doing charts and her worldwide clientele is the ground out of which her astrological inspiration is nourished.