This book is about quantum phenomena in two-dimensional (2D) electron systems with extremely strong internal interactions. The central objects of interest are Coulomb liquids, in which the average Coulomb interaction en- ergy per electron is much higher than the mean kinetic energy, and Wigner solids. The main themes are quantum transport in two dimensions and the dynamics of highly correlated electrons in the regime of strong coupling with medium excitations. In typical solids, the mutual interaction energy of charge carriers is of the same order of magnitude as their kinetic energy, and the...