Diffractive Physics at the CERN Large Hadron Collider

After a short introduction on diffraction, I briefly review the framework used to describe non-perturbative QCD phenomena in hadron-hadron interactions. Then I explain why diffractive processes cannot be ignored at LHC and how ALICE, ATLAS, CMS, LHCb and TOTEM study diffraction, with emphasis on how inclusive particle production measurements are normalised to non-single diffractive and inelastic event classes.