David Brainerd: A Man of Prayer by Oswald J Smith.
Between 1742 and his death in 1747 David Brainerd took the gospel to the North American Indians in New Jersey, Pennsylvania and Massachusetts. He willingly ran any risk and accepted any hardship to fulfill his calling as a missionary. The amount of work which he achieved in such unpromising and difficult circumstances now seems almost incredible. Yet Brainerd did his greatest work by prayer. He was in the depths of the forests alone, unable to speak the language of the Indians, but he spent whole days in prayer for he knew that anything he might do must be absolutely dependent upon the power of God.