This chapter introduces the evolving landscape of national security and intelligence oversight in Canada, contextualized within key legislative and operational developments since 2017. It highlights the growing complexity of Canada’s intelligence environment and sets out the book’s central objective: to evaluate the impact of enhanced oversight mechanisms on the operational effectiveness and accountability of the Canadian Security Intelligence Service (CSIS) and the Communications Security Establishment (CSE). These mechanisms—principally the National Security and Intelligence Review Agency (NSIRA), the National Security and Intelligence Committee of Parliamentarians (NSICOP), and the Office of the Intelligence Commissioner (IC)—form an enhanced oversight framework that has reshaped authorization, review, and reporting processes across Canada’s intelligence community. The chapter offers a detailed analysis of this comprehensive system of accountability, transparency, and legal compliance, examining the mandates, statutory authorities, and areas of potential overlap among the oversight bodies. It also provides in-depth institutional reviews of CSIS and CSE, exploring how each agency functions. To situate the Canadian model within a broader comparative context, the chapter examines oversight frameworks in other Five Eyes countries as well as select non-Five Eyes jurisdictions. It further assesses a series of influential policy events, legislative debates, and political developments that shaped the emergence of this oversight regime. This foundational chapter introduces the framework for assessing whether Canada’s enhanced intelligence oversight mechanisms strike a viable balance between democratic accountability and the operational autonomy of agencies such as CSIS and CSE. It further outlines the evaluative lens through which the performance of these agencies—particularly in addressing foreign interference—will be analyzed, in light of the constraints and possibilities embedded in the current oversight architecture.