Tomorrow optical interferometry: astrophysical prospects and instrumental issues

Interferometry has brought many new constraints in optical astronomy in the recent years. A major leap in this field is the opening of large interferometric facilities like the Very Large Telescope Interferometer and the Keck Interferometer to the astronomical community. Planning for the future is both easy --most specialists know in which directions to develop interferometry-- and difficult because of the increasing complexity of the technique. I present a short status of interferometry today. Then I detail the possible astrophysical prospects. Finally I address some important instrumental issues that are decisive for the future of interferometry.