Introduction to the Pomeron

Elements of the pomeron phenomenology within the Regge pole exchange picture are recalled. This includes discussion of the high energy behaviour of total cross-sections, the triple pomeron limit of the diffractive dissociation and the single particle distributions in the central region. The BFKL pomeron and QCD expectations for the small $x$ behaviour of the deep inelastic scattering structure functions are discussed. The dedicated measurements of the hadronic final state in deep inelastic scattering at small $x$ probing the QCD pomeron are described. The deep inelastic diffraction is also discussed.