Fifty years ago the search for the first Brown Dwarf (BD) was raging among various teams over the world. After several years of intense studies, in September 1995 the first BD were announced in the Pleiades cluster and as a companion to the bright star Gl229, starting a new era in astrophysics. Since then, the field has grown significantly with thousands of BDs known with different spectral types, ages, and metallicities. However the first truly unambiguous halo BD remain to be identified. Do they exist ? How formation processes of substellar objects differ with metallicity?

In this conference, we will celebrate the 30th anniversary of the discovery of the first brown dwarfs and review the most recent substellar studies with special emphasis on metal-poor objects.