Here are some great books on self-care that I recommend:
The Self-care Solution by Suzy Reading
I love this book because it gives you a very practical and helpful approach to self-care. This book really helped me see the many facets of self-care: it's not all about bubble baths and getting your nails done. Suzy Reading does an excellent job providing some helpful research, without overwhelming you with jargon. This book is a quick read and very actionable.
Trauma Stewardship: An Everyday Guide to Caring for Self While Caring for Others by Laura van Dernoot Lipsky
If you are a caregiver, educator, therapist, or anyone who might witness the trauma of others, this book is for you.