Spectroscopy of very low mass stars and brown dwarfs in young clusters

Spectroscopy provides key information about the membership of brown dwarf candidates in clusters, and allows the study of important evolutionary and structural properties like atmospheric composition, chromospheric activity, lithium depletion and rotation. Indeed, spectroscopy is the technique that has allowed the unambiguous confirmation mainly via the lithum test) of all the known brown dwarfs. In this review, the spectroscopic observations that have been taken to date on very low-mass stars and brown dwarf candidates in clusters are summarized. Particular attention has been paid to the information that we axe obtaining on the early evolution of very low-mass objects.