Some of these books are out of print, but can be purchased used at Amazon.
I do not agree with everything in these books, but have found these authors and their books helpful.Always search the Scriptures to see if what is written is true.
Prayer See also Andrew Murray and Charles G. Finney
I read this book in 1986, and these principles are still a major part of my prayer life.
This is a companion volume to the Principles book.
See also E.M. Bounds