I hope this helps for more research on the WWW. Take care and God bless
That might not be the best of the best, but "The Complete Book of Essential Oils and Aromatherapy" by Valerie Ann Worwood is great. It gives you the uses, recipes and all sorts of useful information. I use it as d a constant reference guide.
Hope that helps
My absolute favorite is aromatherapy, AZ by Patricia Davis. I also enjoyed this course www.aromatherapyonlinecourse.com Enjoy!