This lecture presents a short review of the main features of diffractive
processes and QCD inspired models. It includes the following topics: (1)
Quantum mechanics of diffraction: general properties; (2) Color dipole
description of diffraction; (3) Color transparency; (4) Soft diffraction in
hard reactions: DIS, Drell-Yan, Higgs production; (5) Why Pomerons interact
weakly; (6) Small gluonic spots in the proton; (7) Diffraction near the
unitarity bound: the Goulianos-Schlein "puzzle"; (8) Diffraction on nuclei:
diffractive Color Glass; (9) CGC and gluon shadowing.Comment: Based on the lecture given by B.K. at I LAWHEP, Porto Alegre, Brazil,
December 1-3, 200