  In the past years there has been a revival of hadron spectroscopy. Many
interesting new hadron states were discovered experimentally, some of which do
not fit easily into the quark model. This situation motivated a vigorous
theoretical activity. This is a rapidly evolving field with enormous amount of
new experimental information. In the present report we include and discuss data
which were released very recently. The present review is the first one written
from the perspective of QCD sum rules (QCDSR), where we present the main steps
of concrete calculations and compare the results with other approaches and with
experimental data.
