The roof over it all, and the landscape of products around Event Sourcing, CQRS, and Domain-Driven Design.
Every system has a story, but most systems keep only its last page: what is true right now, not how it came to be. What gets lost are the answers to questions nobody has asked yet – why something happened, what was known at the time, and what can be learned from it.
The products around Event Sourcing, CQRS, and Domain-Driven Design, ours included – all in the same form, along the five stages, and described without evaluation.