  Observations of the Sun and solar-type stars continue to reveal phenomena
whose understanding is very likely to require a nonlinear framework. Here we
shall concentrate on two such phenomena, namely the grand minima type behaviour
observed in the Sun and solar-type stars and the recent dynamical variations of
the differential rotation in the solar convection zone, deduced from the
helioseismic observations, and discuss how their explanations have recently
motivated the development/employment of novel ideas from nonlinear dynamics.
