Margaret Cavendish Bentinck, the 2nd Duchess of Portland (1715-1785), was one of the wealthiest women in eighteenth-century Britain. She collected fine and decorative arts (the Portland Vase was her most famous acquisition), but her great love was natural history, and shells in particular. Over the course of twenty years, she amassed the largest shell collection of her time, which was sold after her death in a spectacular auction. Beth Fowkes Tobin illuminates the interlocking issues surrounding the global circulation of natural resources, the commodification of nature, and the construction of scientific value through the lens of one woman's marvelous collection. This unique study tells the story of the collection's formation and dispersal-about the sailors and naturalists who ferried rare specimens across oceans and the dealers' shops and connoisseurs' cabinets on the other side of the world. Exquisitely illustrated, this book brings to life Enlightenment natural history and its cultures of collecting, scientific expeditions, and vibrant visual culture.