I think given our present subject, it is very worthwhile to read. I'd highly recommend the book, which is free over the internet.
I don't necessarily agree with all of Mr. North's theology, but this book, as far as I know, is the only one of it's kind that actually charts the liberal takeover of a denomination. It is superbly researched. It is available for free (!) on his website. See the link below.
HERE BEGINS THE EXCERPT, TAKEN FROM THE "FORWARD"...
This book is about a conflict between two mighty religions, Christianity and humanism. It is also about a third religious tradition that was caught in the middle, whose adherents were forced by circumstances to decide which side to support: experientialism-pietism. Some of them were Christians; others were humanists. This book is about a number of confusions, both theological and institutional, and their subsequent clarification. It discusses heroes and villains, and it acknowledges that the vast majority of the participants were somewhere in between. This is true of every turning point in history except the rebellion of Adam and Eve, in which there were no innocent bystanders. It is the story of a turning point in the history of the United States.
This is a history of the liberals' strategy of infiltration and conquest of the Northern Presbyterian Church. A similar strategy was carried out in the public schools, the judiciary, the colleges, and the media, but this ecclesiastical battle was the most important battle of the war. It had to be won. Why? Because the fundamental covenantal issues of life are always at bottom theological, not political, educational, or economic. The public testimony of the Presbyterian Church was by far the most theologically rigorous testimony in the country--indeed, in the world. Humanists had to silence this denomination, for it was too influential. The capture of the most theologically articulate large conservative Protestant denomination in the United States was modernism's best-publicized success story of the era. The strategy the modernists used to take over the Presbyterians was used, with modifications, to capture the other large denominations.
This book is more than a history; it is a study in sociological patterns: how institutions and groups adjust in order to survive through history. This is why I focus on a few representative figures. I agree with C. Wright Mills: "No social study that does not come back to the problems of biography, of history and their intersections within a society has completed its intellectual journey." [Emphasis mine.]
http://www.freebooks.com/sidefrm2.htm