  This review describes the composition of the Compact Muon Solenoid (CMS)
detector and the methodology for modelling the heterogeneous CMS magnetic
system, starting with the formulation of the magnetostatics problem for
modelling the magnetic flux of the CMS superconducting solenoid enclosed in a
steel flux-return yoke. The review includes a section on the magnetization
curves of various types of steel used in the CMS magnet yoke. The evolution of
the magnetic system model over 20 years is presented in the discussion section
and is well illustrated by the CMS model layouts and the magnetic flux
distribution.
