In a piezoelectric material an applied uniform strain can induce an electric polarization (or vice-versa). Crystallographic considerations restrict this technologically important property to non-centrosymmetric systems. It can be shown both mathematically and physically, that a non-uniform strain can potentially break the inversion symmetry and induce polarization even in non-piezoelectric dielectrics. The key concept is that all dielectrics (including non-piezoelectric ones) exhibit the aforementioned coupling between strain gradient and polarization-an experimentally verified phenomenon known in some circles as the flexoelectric effect.