In 2001, the Robert Wood Johnson Foundation and the federal government funded The Center for Health Enhancement Systems Studies at the University of Wisconsin – Madison to improve care for people with addiction. They chose the Center because its staff had expertise as systems engineers in designing and improving complex systems, using methods from many disciplines. Center staff soon realized that the existing addiction treatment system, characterized by high staff turnover, treatment of only about 10 percent of people who needed it, and questionable success, warranted wholesale redesign. With additional funding from the Robert Wood Johnson Foundation, Center staff convened in 2004 a two-day meeting of technology experts from several fields (e.g., nanotechnology, bioengineering, social psychology) and people with or family members affected by addiction. This group was tasked with imagining a new addiction treatment system that functioned mainly through technology. This meeting produced a vision that was refined in two follow-up meetings, culminating in December 2005 with the decision to build a smartphone app. In 2008, the National Institute on Alcohol Abuse and Alcoholism funded the development and testing of the app, called A-CHESS. A-CHESS was tested in a randomized clinical trial with 349 recovering alcoholics, following patients for one year. Those with A-CHESS had significantly fewer risky drinking days and greater abstinence than those without it. The app has also been used by a consortium of 15 addiction treatment clinics nationwide, who agreed to share their results and suggestions with the development team in exchange for using the app with their patients. The Veterans Administration used it in its Bath, New York, facility that serves veterans in the Rochester area. A-CHESS also has been used by the drug court system and in 57 inpatient and outpatient facilities. In a study funded by the National Institute on Drug Abuse, clinicians are using A-CHESS to treat addicted patients in primary care clinics in Wisconsin, Montana, and New York City. A-CHESS is now being used by people with opioid addiction.