  Over the past two decades, meson photo- and electroproduction data of
unprecedented quality and quantity have been measured at electromagnetic
facilities worldwide. By contrast, the meson-beam data for the same hadronic
final states are mostly outdated and largely of poor quality, or even
non-existent, and thus provide inadequate input to help interpret, analyze, and
exploit the full potential of the new electromagnetic data. To reap the full
benefit of the high-precision electromagnetic data, new high-statistics data
from measurements with meson beams, with good angle and energy coverage for a
wide range of reactions, are critically needed to advance our knowledge in
baryon and meson spectroscopy and other related areas of hadron physics. To
address this situation, a state-of-the-art meson-beam facility needs to be
constructed. The present letter summarizes unresolved issues in hadron physics
and outlines the vast opportunities and advances that only become possible with
such a facility.
