Contrary to previous assumptions, the deformation processes occurring in amorphous and partially crystalline high polymers cannot be considered as locally uniform but is anisotropic, with the formation of regularly arranged crazes. Newly developed methods of preparation allow for the first time the obtaining of direct evidence of these superlattice structures in many high polymers subjected to uniaxial, biaxial, or multiaxial stretching. The investigations have led to new concepts of the supramolecular structure of high polymers; they extend our knowledge of the relationships between the technological properties and molecular structures of polymers.