Not as addicting as the EIT series but still entertaining.
There were a few inconsistencies that were distracting or maybe it's just me. How was a groupie wearing a thong in 1974? Some of the slang didn't fit with that era as well.
It was a good story that did have a few links to the EIT series such as "The Thin Veil" and the Jacobs. It could also be a stand alone book but is better if you read the EIT series to understand the background behind some of the paranormal aspects such as the guardians.