These books, and others by the authors, are very worthwhile and engaging reading.
Getting started
You’ll See It When You Believe It
Dr Wayne Dyer
Creative Visualization
Shakti Gawain
The Road Less Traveled
M. Scott Peck
Spiritual development
Blessing: The Art and the Practice
David Spangler
A Return to Love
Marianne Williamson
Any literature produced by the Brahma Kumaris World Spiritual University
Personal healing
Chakra Clearing
Doreen Virtue Phd.
Daily Guidance from Your Angels
Doreen Virtue Phd.
Angel Almanac
Angela McGerr
Healing arts
Practical Reiki
Richard Ellis
Hands of Light
Barbara Ann Brennan
Essential Reiki
Diane Stein