What is a Metaphysical Book?
A book relating to anything that has no physicality is Metaphysical. This includes the soul and all spiritual concepts that try to define anything that does not consist of matter or physicality in the way we know it.
Metaphysical books are written about subjects such as: On matters of the Soul, GOD, Aura's, and many more metaphysical topics ranging from Hands on Healing to Chakra balancing. It is commonly grouped together with the term New Age but it is vastly different and is usually thought of as deeper and more esoteric in nature.