  In this contribution we review the status and perspectives of direct neutrino
mass experiments. These experiments investigate the kinematics of
$\beta$-decays of specific isotopes ($^3$H, $^{187}$Re, $^{163}$Ho) to derive
model-independent information on the averaged electron (anti-) neutrino mass,
which is formed by the incoherent sum of the neutrino mass eigenstates
contributing to the electron neutrino. We first review the kinematics of
$\beta$-decay and the determination of the neutrino mass, before giving a brief
overview of past neutrino mass measurements (SN1987a-ToF studies, Mainz and
Troitsk experiments for $^3$H, cryo-bolometers for $^{187}$Re). We then
describe the Karlsruhe Tritium Neutrino (KATRIN) experiment which is currently
under construction at Karlsruhe Institute of Technology. The large-scale setup
will use the MAC-E-Filter principle pioneered earlier to push the sensitivity
down to a value of 200 meV(90% C.L.). KATRIN faces many technological
challenges that have to be resolved with regard to source intensity and
stability, as well as precision energy analysis and low background rate close
to the kinematic endpoint of tritium $\beta$-decay at 18.6 keV. We then review
new experimental approaches such as the MARE, ECHO and Project8 experiments,
which offer the promise to perform an independent measurement of the neutrino
mass in the sub-eV region. This variety of methods and the novel technologies
developed in all present and future experiments demonstrate the great potential
of direct neutrino mass experiments in providing vital information on the
absolute mass scale of neutrinos.
