  In this review, I concentrate on describing observations of spatially
resolved emission in symbiotic stars at sub-arcsecond scales. In some of the
closer objects, the highest resolutions discussed here correspond to linear
dimensions similar to the supposed binary separation. A total of 17 stars well
accepted as symbiotics are now observed to show sub-arcsecond structure, almost
twice the number at the time of the last review in 1987. Furthermore, we now
have access to HST imagery to add to radio interferometry. From such
observations we can derive fundamental parameters of the central systems,
investigate the variation of physical parameters across the resolved nebulae
and probe the physical mechanisms of mass loss and interactions between ejecta
and the circumstellar medium.
  Suggestions for future work are made and the potential of new facilities in
both the radio and optical domains is described. This review complements that
by Corradi (this volume) which mainly considers the larger scale emission from
the ionized nebulae of these objects.
