  This article gives an overview of the constitution, physical conditions and
observables of dust in the interstellar medium of nearby galaxies. We first
review the macroscopic, spatial distribution of dust in these objects, and its
consequence on our ability to study grain physics. We also discuss the
possibility to use dust tracers as diagnostic tools. We then survey our current
understanding of the microscopic, intrinsic properties of dust in different
environments, derived from different observables: emission, extinction,
polarization, depletions, over the whole electromagnetic spectrum. Finally, we
summarize the clues of grain evolution, evidenced either on local scales or
over cosmic time. We put in perspective the different evolution scenarios. We
attempt a comprehensive presentation of the main observational constraints,
analysis methods and modelling frameworks of the distinct processes. We do not
cover the dust properties of the Milky Way and distant galaxies, nor
circumstellar or active galactic nucleus torus dust.
