My thanks go to these and many other individuals who shared information or offered criticism: Don Kraig, for suggestions on an early draft of this work; Ron Garst for spending a few evenings talking of oils and incenses; Ed and Marilee Snowden for (again) allowing me access to their library, as well as to Ms. Snowden for proofreading the final manuscript; Daniel Weime for sharing his herbal secrets and allowing some to be published here, and to all my friends who supported and encouraged me during the completion of this work.