  We have used an Imaging Fabry-Perot Spectrophotometer with the Sub-arcsecond
Imaging Spectrograph on the CFHT to measure velocities for 1534 stars in the
globular cluster M15. Combined with previous velocity samples, the total number
of stars with measured velocities in M15 is 1597. The velocity dispersion
profile for M15 remains flat at a value of 11 km/s from a radius of 0.4' into
our innermost reliable point at 0.02' (0.06 pc). This profile and the
previously-published surface brightness profile can be equally well represented
either by a stellar population whose M/L varies with radius from 1.7 in solar
units at large radii to 3 in the central region, or by a population with a
constant M/L of 1.7 and a central black hole of 1000 M_sol. A non-parametric
mass model that assumes no black hole, no rotation, and isotropy constrains the
mass density of M15 to better than 30% at a radius of 0.07 parsecs. Using the
assumption of local thermodynamic equilibrium, we estimate the present-day mass
function and infer a significant number of 0.6-0.7 M_sol objects in the central
few parsecs, 85% of which may be in the form of stellar remnants. Not only do
we detect rotation; we find that the position angle of the projected rotation
axis in the central 10" is 100 degrees different from that of the whole sample.
We also detect an increase in the amplitude of the rotation at small radii.
Although this increase needs to be confirmed with better-seeing data, it may be
the result of a central mass concentration.
