Fresh water has become scarce and will become even more so in the coming years, as continued population growth places ever greater demands on the supply of fresh water. At the same time, options for increasing that supply look to be ever more limited. No longer can we rely on technological solutions to meet growing demand. What we need is better management of the available water supply to ensure it goes further toward meeting basic human needs. But better management requires that we both understand the history underlying our current water regulation regime and think seriously about what changes to the law could be beneficial. For Golden Rules, Mark Kanazawa draws on previously untapped historical sources to trace the emergence of the current framework for resolving water-rights issues to California in the 1850s, when Gold Rush miners flooded the newly formed state. The need to circumscribe water use on private property in support of broader societal objectives brought to light a number of fundamental issues about how water rights ought to be defined and enforced through a system of laws. Many of these issues reverberate in today’s contentious debates about the relative merits of government and market regulation. By understanding how these laws developed across California’s mining camps and common-law courts, we can also gain a better sense of the challenges associated with adopting new property-rights regimes in the twenty-first century.