I present a new theory that is capable of describing coherent backscattering and transmission of waves very close to the mobility edge of localization. Theory is a generalization of the self-consistent theory of localization, devised 20 years ago by Götze, Vollhardt and Wölfle. It is able to deal with boundary condition, an important requirement for a quantitative describtion of coherent backscattering. A comparison will be presented to experiments conducted in Florence and Amsterdam.