"A Different Gospel" by D.R. McConnell is a classical exposure of the Faith movement, the ostensibly Christian and charismatic movement associated with Kenneth Hagin and Kenneth Copeland (in Sweden, Ulf Ekman). What makes this book so fascinating, is that the author is both a charismatic minister (in Holland, of all places) and a person with scholarly training. His book is both a thoroughly documented scholarly work, and a theological polemic. It's sometimes referenced in other scholarly works. But please note that McConnell recieved his degree at the Oral Roberts University, a charismatic school in Oklahoma!
The main thesis of "A Different Gospel" is that the origins of the Faith movement cannot be traced to the Holiness or Pentecostal traditions within American Christianity, nor to the charismatic revivals after World War II, as claimed by other scholars. Rather, Kenneth Hagin, widely recognized as the founder of the Faith movement, got his ideas from E.W. Kenyon, an independent preacher and writer who was neither a Wesleyan nor a Pentecostal. Kenyon was heavily influenced by New Thought and Christian Science, two non-traditional groups often regarded as cults. McConnell thoroughly documents both Kenyon's similarities to the "metaphysical" groups, and proves that Kenyon attended a college whose faculty and students supported New Thought. He also proves that Hagin extensively plagiarized Kenyon's writings, often word for word! Of course, Hagin claims to have gotten his ideas straight from Jesus himself.
Despite being critical of Kenyon's theology, McConnell is surprisingly charitable to him, claiming that Kenyon was misguided rather than malicious, and that he simply wanted to restore the supernatural healing ministry of the Church, something downplayed by the liberal theologians, and also combat New Thought and Christian Science using their own weapons. The author's assesment of Hagin and the Faith movement is less charitable, however, and here he obviously has a point. Many groups within the Faith movement indeed seem to be cultic or cults. (To me, what defines a cult is the use of manipulation and exploitation. McConnell uses a more theological definition.)
Those interested in the Faith movement and the conflicts surrounding it, should also read Hank Hanegraaf's "Christianity in Crisis", another polemical book, but one that goes even deeper into exposing the weird ideas and aberrant practices of the Faith movement.
While I never liked the Faith movement, I always assumed that Faith theology was at bottom evangelical or Pentecostal, with the "prosperity gospel" tacked on as an additional bonus. Indeed, the main Faith congregation here in Sweden, Livets Ord, seems to have moved in such a direction: from an aberrant cult to a group blending main-stream Christianity with the prosperity gospel. However, the books by McConnell and Hanegraaf shows that Faith theology in its pure form has very little to do with main-stream Christianity, or even "regular" Bible belt fundamentalism. Rather, it's a truly bizarre melange of notions reminescent of Gnosticism, Mormonism and Christian Science. Actually, McConnell is somewhat moderate in his criticism of the Faith movement, compared to Hanegraaf who at length documents all their quirky notions (God looks like a man, Heaven is a planet, Adam could fly to the Moon, etc).
Both books are recommended.