An Imaging Fourier transform spectrometer (IFTS) being based on a Michelson Interferometer offers among the various solutions for integral field spectroscopy the unique capability of making possible to combine wide-field coverage, high spectral resolution and high spatial resolution. The spectral resolution can be much higher than with a F-P, with in addition a more flexible choice of resolution and spectral range. Illustration will be given with by results obtained with BEAR, a prototype instrument on various astronomical targets (PNs, Galactic Center, Jupiter). A review of astronomical IFTS in operation or in project will be presented with conclusions for future possible instruments at Dome C and for ELTs.