  The correlation between the luminosities and rotation velocities of galaxies
can be used to estimate distances to late-type galaxies. It is an appropriate
moment to re-evaluate this method given the great deal of new information
available. The major improvements described here include: (a) the template
relations can now be defined by large, complete samples, (b) the samples are
drawn from a wide range of environments, (c) the relations are defined by
photometric information at B,R,I and K' bands, (d) the multi-band information
clarifies problems associated with internal reddening, (e) the template
zero-points are defined by 24 galaxies with accurately known distances, and (f)
the relations are applied to 12 clusters scattered across the sky and out to
velocities of 8,000 km/s. The biggest change from earlier calibrations are
associated with point (e). Roughly a 15% increase in the distance scale has
come about with the five-fold increase in the number of zero-point calibrators.
The overall increase in the distance scale from the luminosity--linewidth
methodology is about 10% after consideration of all factors. Modulo an assumed
distance to the Large Magellanic Cloud of 50 kpc and no metallicity corrections
to the Cepheid calibration, the resulting value of the Hubble Constant is H0 =
77 +- 8 km/s/Mpc where the error is the 95% probable statistical error.
Cummulative systematic errors internal to this analysis should not exceed 10%.
Uncertainties in the distance scale ladder external to this analysis are
estimated at 10%. If the Cepheid calibration is shifted from the LMC to NGC
4258 with a distance established by observations of circum-nuclear masers then
H0 is larger by 12%.
