In Hidden Streams, local historian Brian Mac Aongusa takes the reader on a voyage of discovery of the past in the area of south County Dublin that is now known as Dun Laoghaire-Rathdown. The history of the area has been deeply influenced by many of its rivers and streams, of which there are about thirty in the county. A study of early maps of the county from 1685 onwards reveals a fascinating world of water-powered industries, side by side with the growth of the first township suburbs of Kingstown, Blackrock, Killiney and Ballybrack, and Dalkey. In the twentieth century the unrelenting growth of Dublin's southern suburbs has severely impacted on the landscape and character of the county, causing many of its small rivers and streams to be smothered by developments that have driven them underground, or out of sight or even out of memory. This book seeks to unlock a fascinating new history of Dun Laoghaire-Rathdown viewed from the author's historical and geographical perspectives, as well as from his own deep interest in our ancient rivers and streams.