An urgent cry for revival! One of the greatest authorities on revival in the 20th century, Leonard Ravenhill, shares the principles of Biblical revival. The heart of his teaching is this example. 'This book is like a voice from heaven...its author has been sent by God and has appeared at a critical time in history'. A.W. Tozer From the Back Cover An urgent cry for revival! One of the greatest authorities on revival in the 20th century, Leonard Ravenhill, shares the principles of Biblical revival. The heart of his teaching is this example. ?This book is like a voice from heaven?its author has been sent by God and has appeared at a critical time in history?. A.W. Tozer