Continuous improvement is the real engine of success, but scaling it is tricky. The Theory of Constraints teaches us that at any given time there is one system bottleneck in a value stream and that improvement efforts away from the bottleneck will not improve overall system performance, and may well make it worse. In almost complete contrast, the various approaches to scaling Agile typically mandate that all teams reflect on and improve their practice, not just those situated at the system bottleneck. This advice seems superficially in contradiction to a key lesson of The Theory of Constraints: don’t boil the ocean, focus your improvement efforts. In this talk I will resolve this apparent paradox, showing how both sides have part of the truth, and also how by going a little deeper we can give sage advice on improvement to both people working on the overarching system of work and to those working on front line teams, as well as everyone in between. Join me on a journey through the very practical theory of distributed improvement, culminating in the immodestly titled Prager's Law: "The last thing you should do after making an improvement, is more work".