Wheels of Life is THE book on Chakras. It was written in 1987 by Anodea Judith who has a PHD and is an acclaimed spiritual teacher. The book goes through each chakra one by one, and while it is a huge book, is an enjoyable read.
This fascinating little book describes the authors experience of becoming a Tibetan monk as a child in the 1920s. It is a wonderfully fun read that will make you want to travel to the mountains in Tibet and learn how to meditate and astral project.
This is a best selling and fairly recently written translation of the the Upanishads, the writings of the ancient sages of India, considered the holy texts of Hinduism. It is a great source to learn more about eastern concepts such as reincarnation, karma, etc.