2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47363We recall the definitions and the basic properties of the transversity distributions $h^{q,\bar q}_1(x,Q^2)$ and the corresponding nucleon tensor charges $δq(Q^2)$. We briefly comment on different estimates from several phenomenological models and on the future possible measurements with the polarized $pp$ collider at RHIC-BNL. Recent works on the $Q^2$-evolution of $h^{q,\bar q}_1(x,Q^2)$ are also discussed and their implications on a very useful positivity bound.Latex file, 9 pages and 5 ps fig included with psfig.sty. To appear in the proceedings of the "2nd Zeuthen Spin Physics Workshop", Zeuthen, Germany, September 1997High Energy Physics - Phenomenologytext