This chapter examines Business/IT alignment through three main sections. The first section contextualizes the concept by tracing its theoretical origins and discussing its development into a multidimensional construct, comprising strategic, operational, and individual dimensions. It further introduces the distinction between intellectual and social alignment. The second section focuses on measurement approaches, including the matching and moderation approaches, profile deviation, scoring methods, and maturity models. The final section discusses the relationship between Business/IT alignment and Enterprise Governance of IT (EGIT), drawing on empirical evidence to show how alignment maturity relates to governance mechanisms. The chapter concludes by positioning alignment as a complex, yet measurable, construct relevant to both academic research and practice.