  Topological insulators are a new class of materials that have attracted
significant attention in contemporary condensed matter physics. They are
different from the regular insulators and they display novel quantum properties
that also involve the idea of `topology', an area of mathematics. Some of the
fundamental ideas behind the topological insulators, particularly in
low-dimensional condensed matter systems such as poly-acetylene chains, can be
understood using a simple one-dimensional toy model popularly known as the
Su-Schrieffer-Heeger model or the SSH model. This model can also be used as an
introduction to the topological insulators of higher dimensions. Here we give a
concise description of the SSH model along with a brief review of the
background physics and attempt to understand the ideas of topological
invariants, edge states, and bulk-boundary correspondence using the model.
