This work investigates the environmental degradation of the Hudson River and the efforts of John Cronin to restore its ecological health. The author and photographer document the daily operations of the Riverkeeper, a role dedicated to monitoring industrial pollution and enforcing environmental regulations. By combining visual documentation with narrative reporting, the book illustrates the complex intersection of legal advocacy, scientific monitoring, and community activism required to protect a major waterway.

The text provides a focused, observational account of environmental stewardship that highlights the practical realities of river conservation. Its reliance on photographic evidence and direct reporting suggests a grounded, accessible introduction to the challenges of protecting natural resources from industrial exploitation.