Found in this volume is a survey of Christian doctrine in the light of biology, psychology and mysticism. This work is taken from the Hulsean Lectures given at Cambridge 1926-7; and the Noble Lectures given at Harvard 1926. Also included is an appendix on biochemistry and mental phenomena. The purpose of this book is simple. It is an attempt to show that the work of the Holy Spirit is to be traced in the creative as well as the inspirational energies of the Godhead; that creation, incarnation and inspiration reveal the same eternal value; that biology and psychology bear witness to love rather than to will.