Moore's Law may be dead, but CPUs acquire more cores every year. If you want to minimize response latency in your application, you need to use every last core - without wasting resources that would destroy performance and throughput. Traditional locks grind threads to a halt and are prone to deadlocks, and although actors provide a saner alternative, they compose poorly and are at best weakly-typed. In this presentation, created exclusively for Scalar Conf, John reveals a new alternative to the horrors of traditional concurrency, directly comparing it to other leading approaches in Scala. Witness the beauty, simplicity, and power of declarative concurrency, as you discover how functional programming is the most practical solution to solving the tough challenges of concurrency.