  Recent results concerning the evidence and classification of the
J^{PC}=0^{++} states, obtained with P. Minkowski, are presented: The isoscalars
f_0(980) and f_0(1500) are classified as members of the 0^{++} nonet, while the
broad state called f_0(400-1200) and the state f_0(1370) are considered as
different components of a single broad resonance, the lowest-lying 0^{++}
glueball. Furthermore, we propose the investigation of glueball production in
the fragmentation region of gluon jets.
