The world's 3,400 botanical gardens are home to nearly 150,000 plant species. First established in Europe during the Renaissance, they were initially scientific in nature. In the 18th century, they expanded or evolved into veritable landscaped parks open to the public: arboretums. This book also traces the history of plant classification and conservation. Today, these gardens – at the intersection of ecology, art, and education – play a key role in preserving biodiversity and cultural heritage.