This article discusses the contribution to the specific heat capacity that arises from thermal fluctuations in a magnetically-ordered solid. It considers three temperature ranges, (a) below, (6) in the neighbourhood of, and (c) aboveTewhich is the critical temperature for the existence of the magnetic ordering. For the lowest of these ranges spin-wave theory is applied, and the successes and shortcomings of simple spin-wave dispersion relations and of simple power-law expressions are discussed. Next, more realistic spin-wave dispersion relations, the renormalisation of spin-wave energies, and the properties of low-dimensional magnets are considered. For temperatures aroundTethe discussion is based on the use of critical exponents. AboveTethe magnetic specific heat capacity is related to the magnetic entropy associated with the persistence of short-range magnetic order.