The text discusses building JavaScript microservices with Node.js to address the challenges of maintaining large applications. Microservices architecture structures an application as a collection of loosely coupled services that communicate with each other through lightweight protocols like HTTP. The benefits of this approach include modularity, uniformity, robustness, maintainability, scalability, availability, and testability. To build microservices, developers need to create separate services for different tasks and implement REST APIs for communication between services. The text provides a step-by-step guide on building two JavaScript services, heroes and threats, using Node.js and demonstrates how they communicate with each other through exposed APIs. The code is accompanied by explanations of the implementation and testing of the services. The authors highlight the importance of delegating responsibility to separate applications and communicating between services to achieve a distributed system architecture with Node.js.