Liquid crystal paradigms of condensed matter physics.

Liquid crystals are intermediate phases between the isotropic liquid and solid crystal phases peculiar to many elongated or disc-like, organic molecules. Although the elementary entities of liquid crystals are complex compared to atoms, their macroscopic behaviour is often controlled by spatial symmetry and they exhibit collective phenomena analogous to simpler materials. In this talk, three topics are presented illustrating why liquid crystals will soon be part of Condensed Matter Physics textbooks. Not only are they beautiful examples of the hierarchy of broken symmetry, they provide new examples of disorder and non-equilibrium phenomena.