E. M. Bounds 
The Weapon of Prayer [EPUB ebook] 

"The life of the individual believer, his personal salvation, and personal Christian graces have their being, bloom, and fruitage in prayer."
Edward Mc Kendree Bounds
Edward Mc Kendree Bounds (August 15, 1835 – August 24, 1913) prominently known as E.M. Bounds, was an American author, attorney, and member of the Methodist Episcopal Church South clergy. He is known for writing 11 books, nine of which focused on the subject of prayer. Only two of Bounds' books were published before he died. After his death, Rev. Claudius (Claude) Lysias Chilton, Jr., grandson of William Parish Chilton and admirer of Bounds, worked on preserving and preparing Bounds' collection of manuscripts for publication.