After exploring the initial three chapters, you have a solid knowledge base to distinguish between the microservices style of software architecture and the traditional monolithic approach. You have learned the technique of breaking down the monolith into multiple small, logical, and physically separate groupings called microservices, thereby improving scalability, flexibility, and resilience. While in the traditional monolithic schema of architecture, you have a single, unified application to manage, the same application, when redesigned into a microservices architecture, becomes a collection of independently deployed services. Hence, many more concerns, like inter-microservice communications, will pop up. This chapter explores the details of this new set of architectural concerns. It also explores a few relevant trends in the software paradigm that have compelled software architects to move away from traditional architectural styles.