Lithium and proton-capture elements in globular clusters: implications
  for multiple population scenarios
  In the multiple population framework, a number of studies have been
accomplished in order to explore the behaviour of lithium with proton-capture
element abundances (e.g., Na, O, Al) in globular cluster stars. Lithium offers
perhaps one of the most severe constraints on the stellar source of internal
pollution in these complex systems. Given its vulnerability, we expect that
material processed via the hot H-burning, re-cycled in the formation of the
subsequent generation(s), is free of Li. However, Nature breaks our
expectations. In this contribution, we will review the current status of this
field, by examining the controversial, surprising results and implications.
