Explore event sourcing and Command Query Responsibility Segregation (CQRS) in this comprehensive Scala Days Copenhagen 2017 conference talk. Gain a quick introduction to these scalable patterns for managing application state, then dive into the Lagom Persistence module of the Lagom Microservices Framework. Learn how to implement these concepts in Scala, understand the underlying mechanisms, and examine potential challenges. Compare alternative implementations and discover key factors to consider when evaluating different approaches. Through examples like cargo tracking, uncover the benefits of domain-driven design, event handling, and persistent entities. Investigate scalability, efficiency, and continuous read projections in event sourcing. Conclude with a look at Scala frameworks and a Q&A session to solidify your understanding of these powerful patterns.