Direct detection and imaging of Exo-Earths is a prime candidate for the next Astrophysics flagship mission. Much effort
is focused on developing the mission concept and technology to enable the direct imaging of an Exo-Earth. However,
several key astronomical unknowns stand in the way of a fully optimized Exo-Earth imaging mission, the primary of
which is the uncertainty in the Exo-Zodi brightness. By analogy to our own Zodiacal dust, Exo-Zodiacal dust is
predicted to exist in the habitable zones of other stars, exactly in the locations where Exo-Earths would reside. Reflected
light from this dust could be a primary background contribution to measurements of the Exo-Earth.
We propose a mission concept called the Exo-Zodi Mapper (EZM) to obtain definitive measurements of the brightness
of the Exo-Zodi dust around target stars which are the prime targets for a future mission aimed at the direct detection of
Exo-Earths. Our mission concept uses a medium sized starshade that works with the James Webb Space Telescope to
image and characterize the brightness and distribution of Exo-Zodiacal dust around ~40 primary target stars. This
measurement would provide more precise requirements for the eventual Exo-Earth flagship mission, which may translate
into significant savings. In addition, EZM can provide a host of ancillary science information on these important targets,
including detailed maps of their dust distribution, studies of outer, giant planets, and exploration of the overall
architecture of these planetary systems. The EZM starshade can also be used to enable high-contrast imaging of other
targets of value to the astronomical community such as debris disks around young stars. We present an overview of the
science that motivated the mission concept, the driving requirements, and the top level mission architecture.