With the rise of Pentecostalism in the early twentieth century and growth in the charismatic movement since, a resurgence of interest in the Holy Spirit and Christian spirituality in both theology and the church's life has become evident. Along with increased interest in the doctrine of the Holy Spirit, there are criticisms of the treatment of the doctrine in church history for having neglected the Holy Spirit in both theology and the church's life. Critical studies of the treatments of the doctrine of the Holy Spirit in church history have been laboriously conducted. However, there have not been many studies on the doctrine of the Holy Spirit in Reformed orthodoxy, particularly in its confessional standards. Recognizing the gap in the history of scholarship, this work explores and provides a systematic account of the person and some aspects of the work of the Holy Spirit as presented in the major Reformed confessions and catechisms of the sixteenth and seventeenth centuries. Attention is particularly given to those aspects of the work of the Holy Spirit that have not been greatly explored but are pertinent to contemporary discussions.