  Glueballs and other resonances with large gluonic components are predicted as
bound states by Quantum Chromodynamics (QCD). The lightest (scalar) glueball is
estimated to have a mass in the range from 1 to 2 GeV/c**2; a pseudoscalar and
tensor glueball are expected at higher masses. Many different experiments
exploiting a large variety of production mechanisms have presented results in
recent years on light mesons with J(PC) = 0(++), 0(-+), and 2(++) quantum
numbers. This review looks at the experimental status of glueballs. Good
evidence exists for a scalar glueball which is mixed with nearby mesons, but a
full understanding is still missing. Evidence for tensor and pseudoscalar
glueballs are weak at best. Theoretical expectations of phenomenological models
and QCD on the lattice are briefly discussed.

High Energy Physics - Experiment;Nuclear Experiment