The evolution of police and probation in the United States can be conveniently divided into three stages: (1) the pre-20th century, (2) 20th century policy and practice, and (3) the emerging era of effective partnerships. Policing and probation have common roots in their efforts to deal with similar societal problems. Both organizations also rest on the beliefs that society will be safer if future crimes can be prevented and that actions by members of both organizations can be effective in preventing those crimes. A major paradigm shift in the role of government occurred at the beginning of the 20th century and began the Progressive Era. Police and probation tended to be isolated from one another during most of the 20th century, despite the obvious need for effective communication and organizational cooperation. However, changes in the 1960s and 1970s laid the groundwork for unexpected future collaborations between probation and police. Crime increases, expanding probation caseloads, and funding restrictions in the 1980s led to changes in probation and police practices and the resulting ability to move toward more collaboration. Community policing programs sought out new partnerships between the police and previously unconnected government agencies such as probation. Efforts in Massachusetts exemplify these collaborations. These partnerships are a work in progress, but the movement toward collaboration holds great promise for solving problems. 17 references