This book is a sequel to a Study of primitive Christian teaching upon the Holy Spirit which was published three years ago. Like its predecessor, it is not a formal contribution to the History of Doctrine, and does not claim the attention of professed students of theology. Some attempt was made to supply the needs of students in my two early books, On the Early History of the Doctrine of the Holy Spirit (1873), and On the History of the Doctrine of the Procession (1876). Both are now out of print, but their substance is accessible in an article (Holy Ghost) which may be found in the third volume of the Dictionary of Christian Biography (1882); and to that article I must refer those who desire a fuller or more exact treatment of certain aspects of the subject than this book can offer.<br><br>In the present Study I have had in view chiefly those readers of The Holy Spirit in the New Testament who may wish to pursue the subject into post-apostolic times, but for various reasons are unable to examine the original documents for themselves. With the view of preparing for this book I have read again all the more important Greek and Latin patristic authorities of the first five centuries, and a few which belong to the sixth, seventh, and eighth, and have sought to form my impressions afresh.