  The last two decades have witnessed the discovery of a myriad of new and
unexpected hadrons. The future holds more surprises for us, thanks to
new-generation experiments. Understanding the signals and determining the
properties of the states requires a parallel theoretical effort. To make full
use of available and forthcoming data, a careful amplitude modeling is
required, together with a sound treatment of the statistical uncertainties, and
a systematic survey of the model dependencies. We review the contributions made
by the Joint Physics Analysis Center to the field of hadron spectroscopy.
