The first of the “Three-Island” Euroconferences on Stellar Clusters and Associations was dedicated to Very Low-Mass Stars and Brown Dwarfs. It was held in the island of La Palma (May 11–15, 1998) where the Observatory of Roque de los Muchachos is located. These series of Euroconferences, an initiative led by Roberto Pallavicini (co-ordinator), Thierry Montmerle and Rafael Rebolo, are aimed to cover a very broad range of astrophysical problems where research on Stellar Clusters and Associations is crucial. In the first Euroconference, we reviewed, in a beautiful location, problems related to the formation, evolution and characterization of objects at the bottom of the Main Sequence and beyond. The first discoveries of brown dwarfs in 1995 have been followed by numerous detections in stellar clusters and in the solar vicinity. The drastic increase in the number of known examples of these fascinating objects, which suggests they are indeed very numerous in the Galaxy, has allowed a better comparison with theoretical predictions and a better and faster development of our knowledge about their physical conditions.

Some of the questions addressed in the papers compiled in this volume and delivered by active researchers in the field are: how very low-mass stars and brown dwarfs form, how many there are in the Galaxy, how they evolve, what the physical conditions of their atmospheres and interiors are, how magnetic activity develops in fully convective objects, if they generate magnetic fields, if brown dwarfs are chromospherically active and show coronae.