  M dwarfs with masses 0.1 <= M/M_sol <= 0.3 are under increasing scrutiny
because these fully convective stars pose interesting astrophysical questions
regarding their magnetic activity and angular momentum history. They also
afford the most accessible near-future opportunity to study the atmospheres of
terrestrial planets. Because they are intrinsically low in luminosity, the
identification of the nearest examples of these M dwarfs is essential for
progress. We present the volume-complete, all-sky list of 512 M dwarfs with
masses 0.1 <= M/M_sol <= 0.3 and with trigonometric distances placing them
within 15 pc (parallax >= 66.67 mas) from which we have created a sample of 413
M dwarfs for spectroscopic study. We present the mass function for these 512 M
dwarfs, which increases with decreasing stellar mass in linear mass space, but
is flat in logarithmic mass space. As part of this sample, we present new VRI
photometry for 17 targets, measured as a result of the RECONS group's long-term
work at the CTIO/SMARTS 0.9m telescope. We also note the details of targets
that are known to be members of multiple systems and find a preliminary
multiplicity rate of 21 +/- 2% for the primary M dwarfs in our sample, when
considering known stellar and brown dwarf companions at all separations from
their primaries. We further find that 43 +/- 2% of all M dwarfs with masses 0.1
<= M/M_sol <= 0.3 are found in multiple systems with primary stars of all
masses within 15 pc.
