PSB7 spirit box s are in wide use today by many in the paranormal field while many books are detailing on how to build one this book discusses some theories in physics as to how they are actually speaking to beings and deceased loved ones. A great deal of research went into this book from a father and his 14 year old son who helped write it. New ideas on radio theory that might help other researchers in this field to continue to bravely go forward in this work.