Along with Gerald Gardner, Alex Sanders, and Janet and Stewart Farrar, one of the most influential researchers into the old ways whose writings form the foundation of Wicca. Though she often denied the appellation, many neopagans hailed her as "the mother of modern witchcraft".
Doreen was introduced to the craft when she met Gardner in 1952, a year after Britain repealed its last law banning witchcraft. In 1953 she was initiated into his coven, soon becoming its high priestess. By 1959, after collaborating with Gardner on his book "The Meaning of Witchcraft", she left to found her own group.
Doreen published many books of her own from that point forward, including "An ABC of Witchcraft Past and Present", "Natural Magic", "The Rebirth of Witchcraft", and "Witchcraft: A Tradition Renewed", and many of her chants and invocations are widely known. The Charge of the Goddess is one of her most famous writings.
She passed on on 4 October 1999.
Doreen's writings are so widely known and are passed on so quickly that they serve as a good barometer of whether an individual witch (or a whole group) is the genuine article, or just a wannabee. A traditionalist initiate I know once told me a story of how Doreen was present at a gathering where a priest of another tradition was leading the opening invocation. Supposedly, this invocation was an ancient chant handed down through several generations. After he had called out just one line of it, though, Doreen burst out laughing. Now, laughter is normally a Good Thing in circle, as it's an expression of pleasure, and "all acts of love and pleasure are My rituals" (from The Charge of the Goddess). But there's a time and a place for everything, and it's usually bad form to laugh when the priest or priestess is trying to open the circle.
The priest calmly (but with clear upset) asked what was so funny. Doreen said something to the effect of "don't give me that hooey about that chant being handed down through the years, I wrote that in the fifties."
Now, the poor priest may well have been told that this chant was from an ancient tradition, but someone somewhere in that group hadn't done enough of their homework. Since most Wiccans tend to grab anything that isn't nailed down and doesn't run too fast (and if it is nailed down, that's why the God and Goddess gave us claw hammers and prybars), it's easy to end up grabbing a nice chant that isn't as old as one might like to believe, or to unknowingly (or knowingly) pass off someone else's work as your own.
The moral: check your sources.