  We undertook a long term project, DIRECT, to obtain the direct distances to
two important galaxies in the cosmological distance ladder -- M31 and M33,
using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult
to detect, detached eclipsing binaries provide us with the potential to
determine these distances with an accuracy better than 5%. The massive
photometry obtained in order to detect DEBs provides us with good light curves
for the Cepheid variables. These are essential to the parallel project to
derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both
Cepheids and eclipsing binaries the distance estimates will be free of any
intermediate steps.
  As a first step of the DIRECT project, between September 1996 and January
1997 we have obtained 36 full nights on the Michigan-Dartmouth-MIT (MDM)
1.3-meter telescope and 45 full/partial nights on the F. L. Whipple Observatory
(FLWO) 1.2-meter telescope to search for detached eclipsing binaries and new
Cepheids in the M31 and the M33 galaxies. In this paper, first in the series,
we present the catalog of variable stars, most of them newly detected, found in
the field M31B ($\alpha_{2000.0},\delta_{2000}=11.20\deg,41.59\deg$). We have
found 85 variable stars: 12 eclipsing binaries, 38 Cepheids and 35 other
periodic, possible long period or non-periodic variables. The catalog of
variables, as well as their photometry and finding charts, are available using
the anonymous ftp service and the WWW.
