This document discusses reactive data-centric architectures using the Data Distribution Service (DDS) standard. It provides an overview of DDS and how it enables data-centric and reactive systems. Key points include: - DDS provides a distributed data space that allows applications to asynchronously read and write data while enjoying spatial and temporal decoupling. - Data models in DDS define application data types and provide type-safety and content-based routing of data. - Quality of service policies in DDS control properties of data sharing like reliability, latency, ownership, etc. - Examples show how to write and read DDS data in C++ and Python by creating publishers, subscribers, and data readers/writers