  (Shortened) The combination of lensing and stellar dynamics breaks the
mass-anisotropy degeneracy and provides stringent constraints on the mass
distribution in early-type (E/S0) galaxies out to z~1. We present the combined
results from the five field E/S0 lens galaxies at z=0.5-1.0 analyzed as part of
the LSD Survey. We find: (i) Constant M/L models are ruled out at >99% CL for
all five E/S0s. The projected dark-matter mass fractions inside the Einstein
(effective) radius is f_DM=0.37-0.72 (0.15-0.65) for isotropic models. (ii) The
average power-law slope of the total mass distribution is <\gamma'>=1.75+-0.10
for isotropic models with 0.20 rms scatter. The ratio between the observed
central stellar velocity dispersion and that from the best-fit SIE lens model
is <f_SIE>=<\sigma/\sigma_SIE>=0.87+-0.04 with 0.08 rms. Considering that
\gamma'>2 and f_SIE>1 have been reported for other systems, we conclude that
there is a significant intrinsic scatter in the density slopes of E/S0s (rms
\~15%). Hence, the isothermal approximation is not sufficiently accurate for
applications that depend critically on the slope of the mass density profile
(i.e. measuring H_0). (iii) The inner power-law slope of the dark-matter halo
is constrained to be <\gamma>=1.3(+0.2/-0.4) (68% CL) for the isotropic model
or an upper limit of \gamma<0.6, if the galaxies are radially anisotropic
(r_i=R_e). This is consistent with numerical simulations only for an isotropic
velocity ellipsoid and if baryonic collapse and star-formation do not steepen
dark-matter density profiles. (iv) The average stellar M/L evolves as
d\log(M_*/L_B)/dz =-0.72+-0.10, obtained via the FP. Based on lensing and
dynamics we find d\log(M_*/L_B)/dz=-0.75+-0.17, indicating that the M/L ratio
evolution for our sample of field E/S0s is faster than those in clusters.
