Architectural patterns can be classified based on different properties. Componentization is a good example of one such property. Architectural patterns can be applied to monolithic systems or distributed systems. In this book, we will focus on the architectural patterns specific to Microservices-based distributed systems. Within this sub set we have classified the architectural patterns discussed in this book based on the problem type. This will ease the task for a solution architect to map a problem to an architectural pattern. The following are the architectural patterns we address through the patterns discussed in this book.