  The Curie-Weiss model is an exactly soluble model of ferromagnetism that
allows one to study in detail the thermodynamic functions, in particular their
properties in the neighbourhood of the critical temperature. In this model
every magnetic moment interacts with every other magnetic moment. Because of
its simplicity and because of the correctness of at least of some of its
predictions, the Curie-Weiss model occupies an important place in the
statistical mechanics literature and its application to information theory. It
is frequently presented as an introduction to the Ising model or to spin glass
models, and usually only general features of the Curie-Weiss model are
presented. We discuss here properties of this model in a rather detailed way.
We present the exact, approximate and numerical results for this particular
model. The exact expression for the limiting magnetic field is derived.
