  Developing satisfactory methodology for the analysis of Markov random field
is a very challenging task. Indeed, due to the Markovian dependence structure,
the normalizing constant of the fields cannot be computed using standard
analytical or numerical methods. This forms a central issue for any statistical
approach as the likelihood is an integral part of the procedure. Furthermore,
such unobserved fields cannot be integrated out and the likelihood evaluation
becomes a doubly intractable problem. This report gives an overview of some of
the methods used in the literature to analyse such observed or unobserved
random fields.
