Colorado Governor John Hickenlooper described legalization as one of the major experiments of the 21st century. Washington has followed Colorado into the “brave new world” of legalization. California now proposes to add recreational legalization to its present medical-use status. Increasingly, there is evidence of beneficial, therapeutic outcomes for various medical conditions. Legalization also promises to diminish the social and economic costs of criminalization. But what are the potential risks of widespread use? How will the industry be organized and regulated? What can we learn from experiences in other states and nations?