At the heart of the biodynamic method are the eight preparations used to enhance the health and vitality of the soil: horn manure, horn silica, yarrow, chamomile, nettle, oak bark, dandelion and valerian. In this deeply insightful book, renowned biodynamic expert Manfred Klett explores the principles that underlie the preparations. He looks in detail at each preparation, describing their different properties, how their substances are enhanced and transformed through the stages of preparation, and the effect each preparation has on the soil and plants. Throughout, Klett advocates a holistic approach, which sees farms and gardens as integrated living organisms with the preparations playing a key role in improving the quality of the soil and producing healthy plants. This is essential reading for biodynamic practitioners who want to delve more deeply into the origins and theory of the preparations, and who want to better understand the spiritual principles that underpin how they work.