How to Pray is a Christian Classic by R A Torrey which he wrote around 1900 explaining the principle of prayers to help Christian in their prayer life. The book is still relevant for our times as it takes us through various types of prayers and the benefits of effective prayer. He also identifies the various hindrances to our prayers, but offers guidance as to how to overcome these hindrances. This book will continue to assist Christians in their prayer life for a long time.