  Half a century of work on the light scalar mesons $f_0(500)$, $f_0(980)$,
$K_0^\star(700)$, and $a_0(980)$ is briefly reviewed. After summarising all
light scalar candidates in the Review of Particle Physics since 1963, a
selection of different theoretical and phenomenological descriptions is
presented, including pure meson-meson models, a tetraquark construction,
unitarised quark-meson models, unitarised effective chiral approaches, and a
very recent lattice-QCD simulation.
