A multivariate study of approximately 1,500 ground stone tools (celts) from the Coast Salishan cultural area of British Columbia, Canada, forms the basis of this book. The traditional and often unthinking quest to find types within this largely unclassified class of material formed the starting point to the author's work. When statistical methods failed to discriminate betweenn typological groups, Mackie was forced to think more creatively about the behavioural environment of their use., especially how use-life would alter shape. This book is therefore both a study of stone tools and an exploration into archaeological systematics which problematises the manic classificatory zeal which is such a peculiar feature of most archaeologists.