  We present high-resolution echelle spectroscopy of 676 nearby M dwarfs. Our
measurements include radial velocities, equivalent widths of important
chromospheric emission lines, and rotational velocities for rapidly rotating
stars. We identify several distinct groups by their H alpha properties, and
investigate variations in chromospheric activity amongst early (M0-M2.5) and
mid (M3-M6) dwarfs. Using a volume-limited sample together with a relationship
between age and chromospheric activity, we show that the rate of star formation
in the immediate Solar Neighbourhood has been relatively constant over the last
4 Gyr. In particular our results are inconsistent with recent large bursts of
star formation. We use the correlation between H alpha activity and age as a
function of colour to set constraints on the properties of L and T dwarf
secondary components in binary systems. We also identify a number of
interesting stars, including rapid rotators, radial velocity variables, and
spectroscopic binaries.
