10 $\mu$m interferometry of disks around young stars
  This contribution reviews results from interferometric observations of circumstellar disks around young stars of $\lesssim$3 M$_{\odot}$, performed with the MIDI instrument operating in the 10 $\mu$m spectral region. Two main topics, the disk structure on $\sim$1-10 AU scales and the dust properties in the same region, are illustrated with several examples of MIDI studies, covering various evolutionary stages. The spatially resolved observations largely confirm SED-only based hypotheses on disk structure, yet also reveal degeneracies that may occur in such SED modeling. The properties of the dust on the disk surface show a strong radial dependence: the dust close to the central star has generally larger grain sizes and in particular a much higher crystallinity than the dust in more remote disk regions. 
Roy van Boekel