We give a pedagogical introduction to quantum anomalies,
how they are calculated
using various methods, and why they are important in condensed matter
theory. We discuss axial, chiral, and gravitational anomalies as well
as global anomalies. We illustrate the theory with examples
such as quantum Hall liquids, Fermi liquids, Weyl semi-metals,
topological insulators and topological superconductors. The required
background is basic knowledge of quantum field theory, including
fermions and gauge fields, and some familiarity with path integral and
functional methods. Some knowledge of topological phases of matter is
helpful, but not necessary.