Why do we garden? What are the conceptual origins of ornamental horticulture, and how does that inform a judgment of what might constitute a good garden? How does a garden come to be, and how does a gardener relate to those who share the garden with her? It's surprising that these are questions that mostly remain unexamined, in a world where many people garden passionately. Scholars and theoreticians devote their lives to the study of art or literature or architecture, but somehow gardening philosophy is nearly nonexistent. Garden Thought proposes a structure for understanding horticulture in coherent terms, and for practicing seriously and thoughtfully. There are terms and conceptual structures and parameters that inform those who garden; this is an attempt to articulate them and fit them into a coherent framework.