  The gluonic widths of four leading glueball candidates are determined from
their production in radiative quarkonium decays, allowing quantitative
estimation of their glue content. Lattice predictions for the scalar and tensor
channels seem to be in reasonable agareement with present data (allowing for
mixing with $q \bar{q}$ states). However there is a glueball-like-state in the
pseudoscalar spectrum whose mass is considerably lower than expected from
lattice estimates.
