The book is devoted to a rare topic in theological literature - angelology, i.e. the doctrine of angels and demons, who also have a similar nature as former angels. Written brightly and engagingly, the book comprehensively covers this subject from an Orthodox point of view. All information given in the book is substantiated by Holy Scripture and Orthodox Tradition (the works of the Church Fathers, patericons, theological literature), which gives it a strict and accurate character. At the same time, the sincerity, warmth of the narration, citing genuine cases from people’s lives as examples, make the book relatable and instructive for any Orthodox person. The book was taken from the website of Fr. Konstantin Parkhomenko ( on the Orthodox portal “ABC of Faith” and converted into fb2 format so that everyone interested can carefully familiarize themselves with this rather voluminous work “offline”.