The document discusses microservices and distributed systems. It recommends using microservices and breaking an application into domains like checkout, payment, inventory, and shipping. It describes challenges with distributed systems like unreliable networks and the need for circuit breakers. It also discusses approaches to handling state in distributed systems like using entities, actors, and state machines. It presents event-driven and command-based architectures with messaging buses and recommends lightweight tools. In general, it advocates for embracing events, commands, asynchronous communication and state machines to address challenges with distributed systems.