  When attempting to understand the role of disorder in condensed-matter
physics, one faces severe experimental and theoretical difficulties and many
questions are still open. Two of the most challenging ones, which have been
debated for decades, concern the effect of disorder on superconductivity and
quantum magnetism. Recent progress in ultracold atomic gases paves the way
towards realization of versatile quantum simulators which will be useful to
solve these questions. In addition, ultracold gases offer original situations
and viewpoints, which open new perspectives to the field of disordered systems.
