X-ray diffraction is a well established technique to determine atomic structures. The availability of high intense, low divergence beams provided by synchrotron sources allowed to extend the use of x-ray diffraction to the determination of structures at surfaces and to study the long scale morphology which appears during growth or sputtering. In this talk we will briefly describe the scattering theory and, to give the feeling on the parameters which can be determined, "simple" examples of reconstructed surface determinations will be shown.

More complicates examples as the absorption of C60 molecules on noble metals surfaces will be deeply discussed to show the capabilities and limits of the surface scattering technique.

In the final part of the talk we will describe experiments carried out on laterally nanostructured materials, which have been produced either via lithography and subsequent etching or by self aggregation phenomena. In the first case information on the induced distortion field can be gained while in the second one the time evolution of the ripple periodicity can be precisely determined.