This chapter explores how police in Canada and other regions conceptualize and develop operational responses to major, critical, and public order incidents. It introduces the Ontario Incident Management Structure, which organizes response efforts under an Incident Commander supported by specialized personnel, such as Scribes and Negotiators, and contrasts it with the UK’s Gold, Silver, Bronze (GSB) model. The chapter explains the book’s focus on the Ontario model, breaking down incidents into three core types requiring distinct command skills and response teams. It introduces two guiding frameworks—SMEAC and NRA—which underpin decision-making and risk management. Finally, it sets the stage for upcoming chapters, which will analyze the application of these frameworks in various incident responses.