  The Karlsruhe Tritium Neutrino (KATRIN) experiment will provide a measurement
of the effective electron-neutrino mass, $m(\nu_e)$, based on a precision
measurement of the tritium beta decay spectrum near its endpoint. The effective
mass is an average of the neutrino mass eigenvalues $m_i$ weighted by the
flavor-mass mixing parameters $U_{ei}$ according to the relation $m^2(\nu_e)=
\sum_{i=1}^3 |U_{ei} |^2 m_i^2$. The KATRIN apparatus uses a windowless gaseous
tritium source (WGTS) and a spectrometer based on the MAC-E filter concept to
measure the beta energy spectrum. The KATRIN program is designed to reach a
mass sensitivity of 0.2~eV (90\% C.L.). The collaboration has completed a
series of commissioning measurements and is moving into the first running of
tritium. The KATRIN measurement technique, early commissioning results, and the
future outlook will be presented.
