Nontopological solitons

The use of nontopological solutions to model the quark structure of hadrons is reviewed. The soliton bag, chiral quark-meson and colour-dielectric models are described and the connections and differences between the chiral quark-meson, Nambu-Jona-Lasinio and Skyrme models are outlined. The models fall into two basic classes: those in which hidden chiral symmetry plays a major role, and those in which confinement dominates. The latter include colour-dielectric models and their chiral extensions involving mesons. (orig.)