R. A. Torrey’s books have probably helped more people understand the Bible and have led more souls to Christ than the writings of anyone since the Apostle Paul. Not only was Torrey a great Bible teacher and preacher, he was also filled with the Holy Spirit. He lived what he preached. In his worldwide revival crusades, Torrey presented three main teachings: on Christ, on prayer, and on the person of the Holy Spirit. This book focuses on the latter teaching: The Holy Spirit: Who He Is and What He Does. In addition to Torrey’s teaching on the person of the Holy Spirit, this book presents seven of his shorter teachings, which he shared at Moody Bible Institute, in the churches he pastored, and in various places around the world. These seven teachings are on: The Deity of Jesus Christ. The Power of the Blood. The Power of the Holy Spirit. The Power of Prayer. The Power of the Word of God. The Place of Prayer in Evangelism. Keep Praying Until God Answers. When you read this book, you will receive definite personal blessing in your heart, life, and service, and you will know who the Holy Spirit is and what He does.