In this book, geologist Joseph O'Donoghue takes an openminded approach to the Great Flood legend, as compared to the typically dismissive attitude of academic geology. In parallel with legendary floods, the book also examines the floods of orthodox geology, be they tsunamis, marine invasions or outburst floods from dam-failures. At the beginning of modern science in the seventeenth century, the Flood was accepted as fact, and a number of scientists proposed a comet as the cause, either by impact, or due to gravitational effects of a close fly-past. As geology developed through the eighteenth century, major flooding was generally accepted, and the word "diluvialism" was coined to describe the doctrine. Diluvialism held sway until James Hutton claimed that geological processes took place slowly over long ages, which he deduced at the famous site of Siccar Point in Scotland. This book shows, however, that Hutton was mistaken, and Siccar Point is a testament to catastrophe, not uniformity. Two outburst floods of academic geology are also examined and orthodox explanations are found inadequate. Moving to Mesopotamia and archaeology, and Leonard Woolley's discovery of heavy sediment layers at Ur of the Chaldees, he considers this evidence as attesting to Noah's Flood, and similar layers were found at many sites scattered around Mesopotamia. While orthodox archeology dismissed these anomalous sediment layers as due to mere local floods, heavy sediment layers can only be deposited by large-scale floods. Woolley's estimated date for the Flood was approximately 3100 BCE, and we have a cuneiform tablet that shows a cosmic body in the sky in 3123 BCE, which is here considered the year of the Flood.