Phenomenology of transverse spin: Past, present and future

We summarize the most significant aspects in the study of transverse spin phenomena over the last few decades, focusing on Semi-Inclusive Deep Inelastic Scattering processes and hadronic production in e(+)e(-) annihilations. The phenomenology of transverse-momentum-dependent distribution and fragmentation functions will be reviewed in an in-depth analysis of the most recent developments and of the future perspectives.