  While, in general, interferometers provide high spatial resolution for
imaging small-scale structure (corresponding to high spatial frequencies in the
Fourier plane), single-dishes can be used to image the largest spatial scales
(corresponding to the lowest spatial frequencies), including the total power
(corresponding to zero spatial frequency). For many astrophysical studies, it
is essential to bring `both worlds' together by combining information over a
wide range of spatial frequencies. This article demonstrates the effects of
missing short-spacings, and discusses two main issues: (a) how to provide
missing short-spacings to interferometric data, and (b) how to combine
short-spacing single-dish data with those from an interferometer.
