Book excerpt: This book explains much of what is known currently about freshwater eels, focusing on social and cultural aspects as well as science. A wealth of eel-related material is presented by scientists from around the world, including information on eel fishing, resources, distribution, aquaculture, economics, cuisine, environment and ecosystems, idioms, arts and crafts, tradition, legends, mythology, archaeology and even memorial services. Eels are important as food for humankind and are an interesting model for scientists studying animal migration and reproductive ecology. Their snake-like morphology differentiates them from most other fish, and their unpredictable behaviour that allows them to move over wet land and climb rocks adjacent to waterfalls attracts attention and evokes curiosity. Eels are therefore considered to be enigmatic creatures or metaphysical entities beyond human intelligence; indeed, they have been deified in parts of the world. In recent decades, however, with global populations of eels in sharp decline, some species face a real threat of extinction, and effective conservation strategies and measures are needed. Comparisons across these issues between various countries provide an image of a long-lasting relationship between eels and humankind, and encourage comprehensive and detailed understanding of eels from the perspectives of social, cultural and natural sciences. By promoting understanding of the close relationship between eels and humans, the broader public is engaged and public awareness of eel importance raised, helping to conserve these unique but endangered fish.