Abstract :
I review the physical and mathematical foundations for the theoretical description of the hadron wavefunction at small χ as a Colour Glass Condensate. In this context, I discuss the phenomenon of gluon saturation and some of its remarkable consequences: a new “geometric scaling” for F2, which has been recently identified at HERA, and the unitarization of the hadronic cross-sections at high energy. I show that by combining saturation and confinement one obtains cross-sections which saturate the Froissart bound.
