Please put the words prayer or pray in the search engine.
I dont recommend all the books on prayer on this website.
Books on Prayer For the Olive Tree Bible App
Christian Prayer Resources
http://christianprayerresources.org/
https://twitter.com/PrayerResource
https://www.facebook.com/Christian-Prayer-Resources-179361952653514/
If you have any questions or need help finding a particular video, dvd, tract, book or any other Christian resource in any language of the world, please contact brianformissions@gmail.com