  We discuss our present understanding of the transverse spin structure of the
nucleon and of related properties originating from parton transverse motion.
Starting from the transversity distribution and the ways to access it, we then
address the role played by spin and transverse momentum dependent (TMD)
distributions in azimuthal and transverse single spin asymmetries. The latest
extractions of the Sivers, Collins and transversity functions are also
presented.
