J. Gresham Machen is one of the pivotal figures of modern theological thought. He was involved in many major theological battles, holding the line until he had to leave his seminary and denomination, but at no time being a close-minded obscurantist.

As David Calhoun says in his foreword 'with his rigorous methodology and his complete honesty, Machen in no way contributed to "the scandal of the evangelical mind". Machen was a thinker and a first rate theologian - but he carried his conclusions further than most would dare.

Previous biographies of Machen have tended to emphasise the disputes he was involved in and ignore his early intellectual development that led him to take the positions he did. Previous biographical attempts have tended to stereotype him as a fundamentalist (an identification which he himself generally rejected) and therefore fail to seriously consider Machen in his own terms and in the context of the broader intellectual currents of his day.