[en] Synchrotron radiation may not be an absolute requirement for diffraction experiments on individual monolayers of atoms, but it has certainly stimulated the surge of recent interest because it transforms such experiments from the verge of feasibility to the routinely possible. This chapter reviews the theory of kinematical diffraction from monolayers, describes in detail experimental methods and choice of instrumental parameters, and then lists the sequence of steps necessary to obtain structures from the measurements. (author). 17 refs.; 20 figs