The author has done an exhaustive documentation of the whole diversity of traditional hydraulic structures including their technology of Uttarakhand. This monograph is richly illustrated with photographs maps and several tables. The documentation becomes very precious as the traditional hydraulics today is a vanishing folk heritage. The book demonstrates the direct relevance of this folk scientific heritage in finding solutions to the prevailing water crisis. The author rules out any solution based on privatisation of water. The book strongly pleads for harvesting every drop of rain and every snowflake. The book written in a very lucid style is of interest to both a lay reader and a specialist interested in traditional knowledge culture hydraulics and folk heritage.