This book makes a good stab at explaining the essentials of essential oils.
The author Jennie Harding is pretty much an expert in the field of essential oils as a tutor at the Tisserand Institute in London.
The information is in alphabetical order by the common names of plants and such. There are some practical uses and warnings.
Then it goes off the deep end and you feel that you are reading the stars. There are a few common themes for usage, but most of it is wild speculation or one person’s opinion displayed as universal facts.