This book studies the late 19th century documentation of giant squid sightings, focusing on the monumental squid, Architeuthis, and its relatives. The author presents a collection of first-hand accounts, detailed analyses, and beautiful illustrations to tell a captivating story of the remarkable Architeuthis. The author argues that these creatures, some of the largest invertebrates on earth, inhabit the very deepest, darkest parts of the ocean, only occasionally coming to the surface when sick or dying. Their study provides a unique window into a mysterious and largely unexplored realm. This book paints a vivid, exciting picture of the Architeuthis, certain to thrill and intrigue readers interested in biology, natural history exploration, and the mysteries hidden beneath the sea.