This was a handout that Jackie devised for teaching HND aromatherapy - she had to 'make up' an advanced course as there wasnt one! This is a small part of the research she did for it. It is essentially for those learning aromatherapy and professional aromatherapists but there may be useful information here for therapists generally.
Only qualified aromatherapists may use essential oils on their clients (apart from those bought ready mixed in a base) - it may invalidate your professional indemnity insurance.
Of course, using it for personal use for friends and family is something entirely different.