Abstract
Mesophases are intermediate between unstructured fluids and fully ordered crystalline solids. They often self-assemble at the mesoscale, albeit into defected microstructures, fact that limits their applicability. We describe research on those classes of defects present in one dimensional (lamellar) and two dimensional (columnar) mesophases, their motion and interaction, and their relevance to microstructure coarsening. We also discuss how external shears can be used to accelerate the emergence of macroscopic order in mesophases, and the processes responsible for orientation selection relative to the shear.