What can we learn about coping with rising sea levels from ancient times? The scenario we are facing is scary: within a few decades, sea levels around the world may well rise by a metre or more as glaciers and ice caps melt due to climate change. Large parts of our coastal cities will be flooded, the basic outline of our world will be changed, and torrential rains will present their own challenges. But this is not the first time that people have had to cope with threatening waters, because sea levels have been rising for thousands of years, ever since the end of the last Ice Age. Stories told by the Indigenous people of Australia and the Pacific coast of North America, and those found in the Bible and the Epic of Gilgamesh, as well as Roman and Chinese histories all bear witness to just how traumatic these experiences were. The responses to these challenges varied: people adapted by building dikes, canals, and seawalls, by resorting to prayer or magic, and, very often, by moving out of the way of the rushing waters. Against the Seas explores these stories as well as the various measures being taken today to combat rising waters, focusing on five regions: Indonesia, which will soon move its capital to escape encroachment by the seas; Shanghai, where seawalls protect the busiest port city in the world; the Sundarbans of Bangladesh, whose mangrove forests are constantly challenged by storms and high tides; the Salish Sea, which runs from north of Vancouver to south of Seattle; and the estuary of the St. Lawrence River, where a few initiatives are giving some promising results. What happened in the past and what is being tried today may help us in the future, and, if nothing else, give us hope that we will survive.