This book explains cloud computing and microservices from the perspective of technological evolution, showing the ins and outs as well as the causes and consequences of cloud computing and microservices.The essence of cloud computing is to deepen resource sharing to improve cost-effectiveness by economies of scale and intensification.From a historical perspective, this book summarizes the 2 leaps of the computing paradigm: from stand-alone computing to cluster computing, and then from cluster computing to cloud computing.On the basis of cluster computing, cloud computing has to further solve two key problems : 1) application programs can run everywhere on the cloud; 2) application programs running on the same computer do not interfere with each other.Cloud computing has promoted informationization, bringing about new challenges to servers.Servers are facing the double pressure of increasing data volume and client requests, with the issue of service quality becoming increasingly critical.In this situation, the strategies and methods for servers to achieve efficiency, resilience, scalability, availability, security and consistency, as well as rapid development, rapid revision and upgrade, and fast startup are collectively known as microservice technologies.