  We consider the azimuthal and $P_T$ dependence of hadrons produced in
unpolarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes, within
the factorized QCD parton model. It is shown that at small $P_T$ values, $P_T
\lsim 1$ GeV/c, lowest order contributions, coupled to unintegrated (Transverse
Momentum Dependent) quark distribution and fragmentation functions, describe
all data. At larger $P_T$ values, $P_T \gsim 1$ GeV/c, the usual pQCD higher
order collinear contributions dominate. Having explained the full $P_T$ range
of available data, we give new detailed predictions concerning the azimuthal
and $P_T$ dependence of hadrons which could be measured in ongoing or planned
experiments by HERMES, COMPASS and JLab collaborations.
