  One of the most direct predictions of QCD is the existence of color-singlet
states called Glueballs, which emerge as a consequence of the gluon field
self-interactions. Despite the outstanding success of QCD as a theory of the
strong interaction and decades of experimental and theoretical efforts, all but
the most basic properties of Glueballs are still being debated. In this talk, I
will review efforts aimed to understanding Glueballs and the current status of
Glueball searches, including recent experimental results and lattice
calculations.
