The theory, methodology, technology, and achievements of research on botanical gardens worldwide are for the first time systematically reviewed and summarized, and form the foundation of Botanical Garden Science, PHYTOHORTOLOGY. Chapters 1-8, as Part One, are the “General Introduction and Fundamental Theories and Principles of Botanical Garden Science, PHYTOHORTOLOGY,” and Chapters 9-11, as Part Two, are the text for “Individual Botanical Gardens.” Major achievements in botanical gardens, including research on plant introduction and acclimatization, economic plants, and environmental plants, were presented in this book. Principles and methods for plant conservation in botanical gardens were suggested. Based on the achievements of the authors’ studies of innovations in concepts, theories and practice on plant introduction and acclimatization, ex-situ conservation and stress cultivation of medicinal plants, and plant diversity conservation and utilization in cities were presented. Owing to the importance of visualization, more than 2,000 pictures were selected for this book to show and transfer the information, thought, feelings, and inspiration that could not be expressed by words and text alone. In addition, there are introductions to more than 200 individual botanical gardens all over the world in order to allow readers to easily recognize those botanical gardens, and to deepen their feelings and understanding as well as to create the thought leap in their minds. Many of those pictures were especially provided by botanical gardens both domestic and abroad. This book is appropriate for readers including those who work in botanical gardens, on plant conservation, for landscape and scenery areas and natural protected land, on city construction, on landscape art and architecture, in gardening and landscaping, on education, and policy makers and administration leaders. This English version is translated from the Chinese version published in 2005.