The optical properties of multi-component metal nanostructures (or nanoalloys) are the subject of an
intense and rapidly growing experimental and theoretical activity. In this perspective article, we first
provide a survey of the most recent developments in the field, concerning both theoretical methods,
especially at the first-principles level, and novel results, distinguishing for the convenience of
presentation the sub-field of monolayer-protected multi-component metal clusters from the other alloy
nanosystems. We then discuss a few general concepts which can be drawn from this survey, and offer a
few suggestions on the most promising directions for future research. We hope that making the point in
this fast developing field will provide a framework and a perspective useful to trigger future studies and
advancements.
