Susan Curtis has written a very useful book, balanced between being a MUCH better than average 'coffee table/introduction to aromatherapy' book for the layperson AND a useful adjunct to more in depth books such as
The Complete Guide to Aromatherapy or
Aromatherapy for Health Professionals which are texts of choice for the student (and indeed, professional practitioner) It can be very helpful to have a simpler, but still knowledgeable book to use to refresh back to basics knowledge, rather than feeling a bit overwhelmed by a 'depth text'
Curtis is not an aromatherapist herself, though she is a CAM practitioner. She is also medicines' director of Neal's Yard Remedies (and has been, for many years) Her knowledge of aromatherapy is I surmise a great deal deeper than the knowledge most aromatherapists have of HER modality (homoeopathy).
Unlike the reviewer who said that arranging the oils alphabetically by their botanical name is less useful than by common name, I believe that it is the botanical listing which in part raises it above the 'coffee table set' - who often just repeat the same old same old, copied and lifted from each other.
Curtis has a PROFOUND respect for the plants, not just for the little bottles of essential oils. And it is by understanding the importance of botany that any foundation must happen - whether the user is a professional or a keen layperson anxious to get acquainted with the oils. Buying by COMMON name alone is no guarantee of safety or efficacy. There are several oils which may be sold as 'Lavender' as 'Cedar' as 'Chamomile' to take but 3 examples, and buying one, and thinking it can be used as another, may be disastrous at worst and ineffective at best.
I really like the little usage snapshots/descriptions she produces for her 40 oils. Though a dedicated student will certainly want something more than this, its a great place to start