Fascinating, I am a priest in the Anglican communion and this was a really interesting read. Firstly what does friend actually mean in this context? There was a look at the biblical text and when and where satan is referred to. Paul, who refers very little to the devil and only really in the context of his demise. The author has a good dig into Ephesians and all the references to the devil there, some more subtle than others, the temptation scene in Mark 4 is also looked at in good detail.
The book gives advice about not labelling our enemies as friends of Satan and warns of the dangers of fleshing out such a creature, or absence of good and god.
The author has a good gasp of Hebrew and makes the text clear when a working knowledge is needed. There is a little of the condescension about the tone, however once this is put to one side a solid read.