In 1903, the Presbyterian Church in the United States of America revised the Westminster Confession of Faith because they thought it was deficient regarding the Holy Spirit. In The Spirit of the Age, J. V. Fesko explores the differences between the pre-Enlightenment theology that formed the original Westminster Confession and the post-Enlightenment theology that called for its revision. This study reveals that the pneumatology of the original Westminster Confession is marked by catholicity, whereas the revisions of 1903 represent a doctrine of the Holy Spirt that departed from the common Christianity of the ages. It also reveals that some of the underlying issues linked to the 1903 revisions are still alive today, even among Presbyterian fellowships that refused to adopt the twentieth-century revisions to the Westminster Confession.