Book excerpt: Stromatolites are among the oldest fossils on earth, the only fossils giving evidence of the first 85% of the history of life on Earth. The Arrowhead region of Minnesota, location of some of the most ancient rocks on the planet, is home to a considerable number of stromatolites. This reference imparts a basic, non-technical account along with 636 beautiful images of these most ancient of Earthly collectibles. Covering a diverse variety of stromatolites and the geologic objects that can resemble them, this book is a delight for both stromatophiles, as well as people curious about the early Earth.