  We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD',
which took place at GSI October 12-14, 2015. A group of 26 people met to
discuss the physics of resonances in QCD. The aim of the meeting was defined by
the following three key questions:
  What is needed to understand the physics of resonances in QCD?
  Where does QCD lead us to expect resonances with exotic quantum numbers?
  What experimental efforts are required to arrive at a coherent picture?
  For light mesons and baryons only those with ${\it up}$, ${\it down}$ and
${\it strange}$ quark content were considered. For heavy-light and heavy-heavy
meson systems, those with ${\it charm}$ quarks were the focus. This document
summarizes the discussions by the participants, which in turn led to the
coherent conclusions we present here.
