2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47350In this contribution I discuss transverse momentum dependent quark distributions and their operator structure. Some of the experimental signatures, in particular in Drell-Yan scattering, are given.11 pages with 11 figures, LaTex, uses a4.sty and epsfig.sty. Invited talk at the Symposium "Deep inelastic scattering off polarized targets: theory meets experiment", Sep. 1-5, 1997, ZeuthenHigh Energy Physics - Phenomenologytext