I will present a few recent results derived by our group from observations of clusters of galaxies at optical and X-ray wavelengths.
I will first discuss how environmental effects may modify the shape of galaxy luminosity functions in clusters, based in particular on an ongoing study of Abell 496, where we have derived the luminosity function in a large number of regions.
I will then present the two physical laws that govern the luminous profiles of elliptical galaxies in clusters, and will present how we now are in the process of defining a new distance indicator for clusters, based on the properties of their elliptical galaxies derived from optical images.
Finally, I will show that some properties of the hot X-ray emitting gas appear to be comparable to those of other self gravitating systems such as elliptical galaxies. This can be interpreted as due to the fact that similar physical processes play a role during the formation of these structures.