In the late 1960's, a discarded copy of a collection of papers presented at two conventions held in 1905, sponsored by the General Assembly of the United Presbyterian Church of North America, then published in 1907, made its way from the library of the Westminster Theological Seminary into the hands of William Marshall. Years later, Pastor Marshall was kind enough to share his copy with Still Water Revival Books and write an introduction to their 1992 republication of this invaluable work. I held Pastor Marshall's copy in my hands at the time and benefited greatly in my understanding of psalmody upon reading the 1992 reprint. I still have my SWRB numbered collector's edition and consult it often as a most helpful resource on this subject.
As Pastor Marshall wrote, Dr. David Freeman, a founding member of the OPC and one-time pastor of John Murray in Philadelphia, said "that The Psalms in Worship was the most comprehensive treatment of the subject to be found anywhere." It contains two thoughtful essays each on a series of topics relating to aspects of psalmody in the church. The work was edited by John McNaugher (1857-1947), president of Pittsburgh-Xenia Theological Seminary, who contributed an exegesis on Col. 3.16 and Eph. 5.19. The chapters on "Christ in the Psalms" are among the many highlights in this century-old work which make it so relevant to those studying Biblical worship today.
It is available in various formats from SWRB and also in bound hardcover photocopy from Covenant Protestant Reformed Church in Ballymena, Northern Ireland. Happily, I have found it online at the Internet Archive as well and for those who do not have access to a hardcopy, and wish to study questions relating to the regulative principle of worship, the use of the psalms in the old and new testament church, the history of psalmody in the Christian church, the imprecatory psalms, psalmody and missions, objections to psalmody and many other important questions, consider adding this book to your reading list. Also, Public Domain Reprints is a service that enables one to order softcopy and hardcopy editions of books from Google Books and the Internet Archive. Blessings!