Towns Names of the Holy Spirit is a landmark work in the studies of the Holy Spirit as it is an exhaustive listing of all the names of the Holy Spirit broken up by type, and an appendix of an alphabetical summary list.
Pollock Apologetic Booklets is a work that presents various points of contention, and their answers from Scripture.
Bernard of Clairvaux (I believe he is Catholic) On Loving God is a fifteen chapter work on love, on its degrees, and various other elements of true love
Spring, Gardiner – Distinguishing Traits of Christian Character
Trotter Five Letters on Worship and Ministry in the Spirit.
Vess How to Win our Loved Ones to the Lord (Soulwinning) by Nazarene author Arthur Vess explores the topic of evangelizing our loved ones, focusing on breaking the repetition of unsaved people having unsaved children.
Chafer – True Evangelism a study of what is biblical evangelism