Russell was the fiction editor for Playboy in the 1950's and 1960's. But he was also a skilled writer whose legacy lives on primarily because of his clever horror stories, most notably "Sardonicus," which spawned a William Castle movie but also remains a triumphant homage to the writing style of the late 18th and early 19th centuries. Russell often seemed more at home in the skin of other times, as a period piece ("Sanguinarius") about the bloody Countess, Elizabeth Bathory, was also a model of how to stay true to the style of an earlier era.
The Case Against Satan isn't an homage or a pastiche, however. It's a pretty thoroughly modern novel -- for 1962 America -- with a thoroughly modern protagonist, Father Gregory Sargent. He's plagued by doubts and drink and an abiding lack of faith in the existence of evil as a being, Satan, rather than simply a random, mindless thing.
Russell allows for more ambivalence than Blatty did: even at the end of the novel, some doubts could conceivably remain about who or what Father Sargent has been exorcising. Real-world psychological trauma seems to have instigated the possession. Human evil is at work in the life of 16-year-old Susan Garth. Is it all simply human?
The possession and exorcism scenes are effective and often chilling. Indeed, one of the most chilling moments comes when the Bishop acknowledges that the exorcism might kill Susan -- and chooses to go on anyway because the alternative is far worse in his eyes. Anyone who's heard of the deaths of people being exorcised, even in the past ten years or so, will probably find this decision to be extremely disquieting. But this is a novel, not a pro-exorcism pamphlet or a news story: demons can exist with certainty here. Perhaps.
The characters and situations sometimes tend towards the melodramatic. This is a novel about exorcism, after all, the most potentially melodramatic Catholic rite I can think of. Father Sargent is skilfully drawn, however, as a sympathetic and flawed figure whose doubts seem to have been designed to mirror the doubts of the casual reader. Susan Garth is a little more sketchily drawn -- our sympathies for her emanate from the terrible things she's being put through far moreso than they do from any development of her character. Only an almost stereotypical housekeeper (seriously, I swear she's Mrs. McCarthy from the BBC's current Father Brown series) needs greater depth and clarity; that she's also there to provide a miraculously well-timed anecdote about exorcism in the small (Irish?) town of her birth does not help one's suspension of disbelief.
Of course, our priest and our bishop also ponder the coincidences required to set up the events of the novel, and decide that God has been putting things in place. Metafictionally, that God is of course Ray Russell.
The Case Against Satan also brings in a brusque but ultimately sympathetic homicide detective; an inquisitive Roman Catholic layperson who's a pillar of the Church community and knows it; a squirmy widower as Susan's father; and a former priest of the parish, Father Halloran (Stephen King, take note!), with something to hide. Only an anti-Catholic pamphleteer seems like a complete misstep. He serves a plot function that could probably have taken care of itself. He also seems anachronistic to us now, which couldn't have been helped: this was an America of 1962 that had just gotten used to the idea of its first Roman Catholic president, after all, with all the debates and acrimony over the suitability of such a religionist for America's highest political post. How time flies. American Roman Catholics were yesterday's American Muslims.
In all, The Case Against Satan is a brisk and entertaining read. Some intellectually interesting questions arise as the plot progresses, most interesting a discussion about the Seal of the Confessional. Russell works for the most part in a plain style, putting the ideas and characters at the forefront. The Case Against Satan may be a better novel than The Exorcist. It certainly got there first. Highly recommended.