Abstract. In the light scalar meson sector (M < ∼ 1.8 GeV) one expects at least one qq nonet and a glueball, possibly also multi-quark states. We discuss the present phenomenological evidence for σ and κ particles; if real, they could be members of the lightest (quark or multi-quark) nonet together possibly with a 0 (980) and f 0 (980). Alternatively, the lightest nonet could include f 0 (980) but not σ and κ. Future decisive experimental studies, concerning tests of symmetry relations, especially in B-decays, are outlined.