The book you speak of is good and underscores the need to NOT discount the presence of the evil one. I have read parts of it. The prayers in the back include the ancient Orthodox prayer for deliverance from all evil.
I often wonder how many of the horrific, inexplainable murders we hear of, from O.J. Simpson to recent child murderers are because of the murderer having subjegated themselves somehow (perhaps through the occult, for instance) to actual demon possession which manifested itself at the time of the horrific crime.
May our Lord God keep us strong and protect us from every sort of evil always. Kyrie Eleison!
In Christ our Lord and Saviour,