The link is to a review of Scott Peck's new book on diabolical possession. I haven't read it yet but I would like to when I'm able to find the time.
A few years ago I read his book "People of the Lie." In it he recounts examples of people he met in his psychological work who had freely chosen evil. While many, if not most, sins are the result of human weakness, evil is still a reality and we are capable of choosing it.
Peck's new book is of interest because of his association with Malachi Martin, a controversial Jesuit who took some extreme positions in his later years.