Thirty-seven long-period Cepheid variables have been discovered in the
Fornax cluster spiral galaxy, using the Hubble Space Telescope. The
resulting V and I period-luminosity relations give a true modulus of
*µ*_{0} = 31.28 ± 0.07 mag, corresponding to a
distance of 18.0 ± 0.6 Mpc. A Cepheid distance to the
Fornax cluster offers several means of estimating
the Hubble constant. First,
associating this distance with the Fornax cluster as a whole gives a
local Hubble constant of *H*_{0}=
73 (± 7)_{random} [±
18]_{systematic} km/sec/Mpc. Second, the
Fornax cluster provides a means of calibrating a
wide variety of
secondary distance indicators. Recalibrating the Tully-Fisher
relation using NGC 1365 and 6 nearby spiral galaxies, applied to 15
clusters out to 100 Mpc gives *H*_{0} =
76 (± 2)_{r} [± 8]_{s}
km/sec/Mpc. A broad-based set of differential
moduli established from Fornax out to Abell 2147, nearly a factor of
ten in distance further, gives *H*_{0} = 72 (±
1)_{r} _{s}*H*_{0} =
68 (± 5)_{r} [± 8]_{s}
km/sec/Mpc, out to a distance in excess of
500 Mpc. Seven Cepheid-based distances to groups of galaxies out to
and including the Virgo and Fornax clusters yield *H*_{0} =
70 (± 3)_{r} [± 16]_{s}
km/sec/Mpc. These major distance
determination methods agree to within their statistical errors. The
resulting value of the Hubble constant, encompassing all those
determinations which are based directly on Cepheids or tied to
secondary distance indicators, is found to be *H*_{0} =
72 (± 3)_{r} [± 12]_{s}
km/sec/Mpc, out to cosmologically significant distances.

Hubble (1929)
announced his discovery of the expansion of the Universe
nearly 70 years ago. Despite decades of effort, and continued
improvements in the actual measurement of extragalactic distances,
convergence on a consistent value for the absolute expansion rate, as
parameterized by the Hubble constant, *H*_{0}, was not
forthcoming. However, progress in the last few years has been rapid and
dramatic
(see, for instance,
Freedman, Madore &
Kennicutt 1997;
Mould, Sakai, Hughes & Han 1997;
Tammann & Federspiel 1997).
This accelerated
pace has occurred primarily as a result of the improved resolution of
the Hubble Space Telescope (and its consequent ability to discover
classical Cepheid variables at distances a factor of ten further than
can routinely be achieved from the ground), giving accurate zero
points to a number of recently refined methods which can measure
precise relative distances beyond the realm of the Cepheids. These
combined efforts are providing a more accurate distance scale for
local galaxies, and are indicating a convergence among various
secondary distance indicators in establishing an absolute calibration
of the far-field Hubble flow.

Soon after the December 1993 HST servicing mission it was clear that
the measurement of Cepheids in the Virgo cluster (part of the original
design specifications for the telescope) was feasible
(Freedman *et al.*
1994a).
And although the subsequent discovery of Cepheids in
the Virgo galaxy M100
(Freedman *et al.* 1994b)
and subsequent
refinements
(Ferrarese *et al.*
1996)
were important steps in
resolving outstanding differences in the extragalactic distance scale
(Mould *et al.* 1995),
the Virgo cluster is complex both in its
geometric and its kinematic structure, and there still remain large
uncertainties in both the velocity and distance to this cluster.
Virgo clearly was, and still is, not an ideal test
site for an
unambiguous determination of the cosmological expansion rate or the
calibration of secondary distance indicators. In this paper we
discuss the implications of a Cepheid distance to the next major
clustering of galaxies, the Fornax cluster, which is a much less complicated
system than Virgo.