  We present the 24 micron rest-frame luminosity function (LF) of star-forming
galaxies in the redshift range 0.0 < z < 0.6 constructed from 4047
spectroscopic redshifts from the AGN and Galaxy Evolution Survey of 24 micron
selected sources in the Bootes field of the NOAO Deep Wide-Field Survey. This
sample provides the best available combination of large area (9 deg^2), depth,
and statistically complete spectroscopic observations, allowing us to probe the
evolution of the 24 micron LF of galaxies at low and intermediate redshifts
while minimizing the effects of cosmic variance. In order to use the observed
24 micron luminosity as a tracer for star formation, active galactic nuclei
(AGNs) that could contribute significantly at 24 micron are identified and
excluded from our star-forming galaxy sample based on their mid-IR spectral
energy distributions or the detection of X-ray emission. The evolution of the
24 micron LF of star-forming galaxies for redshifts of z < 0.65 is consistent
with a pure luminosity evolution where the characteristic 24 micron luminosity
evolves as (1+z)^(3.8+/-0.3). We extend our evolutionary study to encompass 0.0
< z < 1.2 by combining our data with that of the Far-Infrared Deep
Extragalactic Legacy Survey. Over this entire redshift range the evolution of
the characteristic 24 micron luminosity is described by a slightly shallower
power law of (1+z)^(3.4+/-0.2). We find a local star formation rate density of
(1.09+/-0.21) x 10^-2 Msun/yr/Mpc^-3, and that it evolves as (1+z)^(3.5+/-0.2)
over 0.0 < z < 1.2. These estimates are in good agreement with the rates using
optical and UV fluxes corrected for the effects of intrinsic extinction in the
observed sources. This agreement confirms that star formation at z <~ 1.2 is
robustly traced by 24 micron observations and that it largely occurs in
obscured regions of galaxies. (Abridged)
