"Prayer Primer: Igniting a Fire Within" by Fr. Thomas Dubay (Amazon link)
"Fire Within" by Fr. Thomas Dubay (Amazon link)
"Difficulties in Mental Prayer" by Fr. Eugene Boylan (Amazon link) (Google Books link)
"Fire Within" by Fr. Thomas Dubay (Amazon link)
"Difficulties in Mental Prayer" by Fr. Eugene Boylan (Amazon link) (Google Books link)