In this chapter, we have learned about what SOA is, and its fundamental characteristics such as service interconnectivity, event-driven and messaging, flexible, service evolution, along with a few other common characteristics. In later sections, we covered SOA principles such as service contract standards, interoperability abstraction, service autonomy, service composability, reusability, and statelessness in detail. 

We also learned about the most common SOA design patterns and where those patterns can be applied so that one can build SOA-compliant services. The patterns that we touched upon are service messaging, message screening, agnostic services, atomic service transaction, authentication broker, message origin authentication, service façade, multiple service contract, service callback, event-driven messaging, service refactoring, and metadata centralization.