I am speaking tomorrow at a conference hosted by my Reformed Presbyterian colleagues to celebrate the 500th anniversary of the Genevan reformer, John Calvin. The main purpose of the conference is to explode some of the myths surrounding Calvin and my particular task is to look at Calvin’s doctrine of the Holy Spirit. The claim of our Pentecostal and charismatic brothers and sisters is that the Holy Spirit has largely been ignored by conservative, reformed churches, and that it is only in the 20th century, through the theology and worship of the Pentecostal and charismatic churches that the “forgotten” Third Person of the Trinity has been re-discovered by the church. The truth is that John Calvin has correctly been identified as “the theologian of the Holy Spirit” and that his theology gives a full and central role to the person and work of the Holy Spirit. I propose to examine Calvin’s emphasis on the work of Holy Spirit in terms of our union with Christ, the doctrine of assurance, the authority of Scripture and the sacraments.