This chapter introduces the FCA rules and English law as the dominant references, but also underlines that much of the regulation and technology analysis applies globally. Three recurring questions throughout the book are first, what aspects of technology are relevant to financial services? Second, what financial regulation applies? Third, if there are not yet relevant legal or regulatory rules, which international standards apply? Key technology terminology is introduced, including Application Programming Interface (API), Artificial Intelligence (AI), Cloud Computing, Cryptography, Machine Learning (ML), Algorithms, Hardware and Software Trading Platforms. The value of thinking critically about all the issues, where the proven Japanese engineering fishbone analysis method can illuminate more risks. Legal and compliance understanding of technology is always behind the speed of technology. Narrowing that gap requires discipline to not only continuously learn financial regulation, but also to constantly dedicate time to understanding cutting-edge technology.