Vertex detection and tracking at future accelerators

Track and vertex reconstruction requirements at LHC and CLIC are considered. A more sophisticated tracking system expands both the range of physics to be studied and the confidence in event signatures. Event characteristics and accelerator environment dictate the techniques, with severe demands on an LHC detector at small radii. Solutions for central and forward tracking are developed, and multivertex reconstruction studied. Research and development needs are identified and limitations on luminosity defined. (author)