In this chapter, the authors discuss various technological, regulatory, and market drivers that triggered the development of 5G and the problems 5G is expected to solve. They then attempt to derive how these affect the Radio Access Network (RAN) architecture and its evolution in order to support 5G, which is the primary focus of the book. Some point outs that the primary technological advancement of 5G is the support of mmWave spectrum, while others believe that 5G is the turning point when cellular networks finally fully embrace virtualization (including RAN), driving down operational costs by opening up RAN to bigger competition. In order to be successful, 5G deployment is likely to require much higher cell densification, at least for the mmWave bands. The importance of standards is unlikely to change with 5G; however, certain market developments affect the way 5G standards are defined and deployed.