Event Sourcing: Greg Young’s GOTO 2014 Talk

HN commenters list it among the best introductions to event sourcing and use it to illustrate storing read-only events instead of mutating state.

Greg Young, who coined CQRS, gives an in-depth GOTO 2014 talk on what event sourcing is, when it is valuable and when it is not, along with its trade-offs and common misconceptions.