I just discovered the little known topic called astral travel a few years ago. It was a side effect from the meditation sessions I started having. I would see things similar to dreams while in deep meditation. I would be in a trance like state. Astral travel has also been called the out of body experience and can be related to a near death experience. The scenario is that everyone has an astral “body” and your spirit travels with this body. You “travel” and visit places in different times and spaces with this astral body.
I began to research this topic and discovered there are not many books written on this topic, though most that were are worth reading. The Astral Projection Workbook by J. H. Brennan is a great book that explains what astral travel is and guides you step by step to experience this phenomenon. Another book which is my favorite and quite possibly the best book written on the subject is Astral Dynamics by Robert Bruce. It goes in depth about the subject, contains exercises, and he even includes some of the journals from his astral experiences in the book. It is very easy to understand, even if you have never heard of this before, and very informational.