Monodisperse nanomaterials with precise morphologies are a vital component of many recent nanotechnologies. One promising synthetic route to prepare particles with defined nonspherical architectures is the crystallization-driven self-assembly (CDSA) of block copolymers. Living CDSA provides access to complex hierarchical nanostructures with impressive morphological and dimensional control; and this complexity enables wide-ranging applications in drug delivery, 10-13 colloid stabilization, catalysis, optoelectronics, and information storage. The 'livingness' of CDSA is achieved by initiating growth from uniform seed crystallites, which provide the nucleation that enables self-assembly to start from a common point (Fig. ). 6,8,10, Realizing the full potential of CDSA for nanostructure synthesis requires a precise understanding of how CDSA particles grow and how this self-assembly process can be controlled.