This book is about the Somerset River Brue, which rises beyond the Somerset Levels from the Mendip Hills to the Wiltshire Downs and southwards, and, along with its tributaries, flows west to the Bristol channel. It describes a whole unit, the River Brue, intermittently from its source to its mouth: a "proper" river, composed of various brooks, and has so much that is unique. Each brook comprising the Brue, the north and south Brew, the Pitt, and most of the Alham, are all fairly ordinary streams, but each has its own history. Downstream, the brooks flow together and the rivers get bigger. The Brue becomes wider and deeper, the volume of water and the upstream length and catchment are greater, so the plants inhabiting it change to those more suitable for the new depth, flow, and substrate. Generally the pollution increases as the river receives more dirty run-off from fields, roads, houses, gardens, and industry.