Spirits of the Sacred Grove was first published under that title in 1998. In 2001, Thorsons republished it under the title of ‘Druid Priestess’ and in 2014 it was re-released under the original title again, by Moon Books. At this point it became available in ebook form for the first time.
This is less a how-to book, more an experiential piece from one of the most significant figures in turn of the century British Druidry. It gives a strong sense of lived Druidry and personal experience, and is a text that has influenced a great many students of Druidry. There is an animist language and a way of speaking about sacred space and experience that has shaped the writing of many of the Druid authors who have since followed in her footsteps.
Emma Restall Orr (also widely known as Bobcat) was at the time of writing this book, a Druid with an international reputation. In recent years she has apparently stepped away from the term ‘Druid’ to explore mysticism.
Emma Restall Orr worked for the Order of Bards Ovates and Druids and was Joint Chief of the British Druid Order for nearly ten years. In 2002 she founded the international Druid Network which, by gaining status as a religious charity in 2010, changed the legal definition of religion in Britain. She is celebrated for her uncompromising views on ethics, environmentalism and personal responsibility, and does still give public talks on occasion.
I've tagged the other incarnations of this book for clarity.