What do we understand about equilibrium in block polymer micelles?

The factors that dictate the choice of micellar morphology - sphere, worm, or vesicle - are generally well known. In contrast, the pathways by which micelles reach equilibrium (either in terms of morphology or aggregation number), are not. Even as simple a question as ``How does the critical micelle concentration depend on chain length?'' does not have a clear answer. The current situation will be summarized, in light of recent experimental results.