What does the foghorn sound like? It sounds huge. It rattles. It rattles you. It is a booming, lonely sound echoing into the vastness of the sea. When Jennifer Lucy Allan hears the foghorn’s colossal bellow for the first time, it marks the beginning of an obsession and a journey deep into the history of a sound that has carved out the identity and the landscape of coastlines around the world, from Scotland to San Francisco. Within its sound is a maritime history of shipwrecks and lighthouse keepers, the story and science of our industrial past, and urban myths relaying tales of foghorns in speaker stacks, blasting out for coastal raves. Here is an odyssey told through the people who battled the sea and the sound, who lived with it and loathed it, and one woman’s intrepid voyage through the howling loneliness of nature.