The Aromatherapy Beauty Guide by Danielle Sade is a fantastic, comprehensive resource that will teach you everything you need to know to create your own natural personal care products using essential oils. You'll learn about the basic ingredients you can use, essential oils that are great for skin care, and the formulations and recipes to create your own personalized skin care products.
Aromatherapy with Essential Oil Diffusers by Karin Parramore is a beautiful black-and-white (and blue) 200-page book filled with information about using essential oils for health and wellness. Like the title suggests, the focus is on diffusing, but you’ll find more than that in this comprehensive book.
The Complete Aromatherapy & Essential Oils Handbook for Everyday Wellness by Nerys Purchon and Lora Cantele is a great handbook for those that are new to the world of essential oils. With more than 400 pages of detailed information you’ll have everything you need (besides your essential oils, of course!) to become more confident about safe essential oil practices.