This book contains the orations that birthed the BioDynamic method. It was not written, it was spoken.
It is a compilation of lectures given by Rudolf Steiner in 1924 at the request of farmers who were experiencing degeneration in their plants and animals from the use of artificial fertilizers.
BioDynamics was the very first reaction to chemical farming and its lessons make more sense today than when they were first offered.
This book is more profound every time you read it. A paragraph is the equivalent of an entire chapter in other books. It covers everything from an articulation of the energetic framework of life to the description of the nature and creation of the BioDynamic preparations (BD500-508).
Anyone interested in plants, or the natural world in general, deserves to read this book.