By addressing four basic and fundamental questions paralleling the SARA problem-solving process, this paper, develops a research agenda for understanding police problems: what are problems; what causes problems; how can we find effective solutions to problems; and how can we learn from problem solving? Police problems are typically described as groups of related incidents of concern to the community and comprised of three elements: (1) problems are groups of incidents; (2) incidents in this group are connected in some meaningful way; and (3) incidents are required to be disturbing or harmful to members of the public. The first topic in a problem-oriented research agenda is the documentation and cataloging of different problem types. In addressing what causes problems, a summary and expansion of the current set of problem theories is conducted by drawing on Routine Activity Theory and other related theories. Routine Activity Theory can help develop a framework for understanding problems through an explanation of crime events. One of the greatest difficulties for problem-oriented policing is when one moves from analyzing a problem to responding to the problem. Professional judgment by beat-level problem solvers is seen as a critical element in developing a solution. Professional judgment includes identifying a problem, collecting information about it, and developing some insights leading to a solution. However, this must be supported by theories and sets of protocols. An example of beat-level problem-solving protocol with its essential characteristics is discussed and presented. The paper closes with a list of research questions designed to improve the science and practice of problem analysis and solution. References