Dust is ubiquitously found in the Universe, even at high redshifts
where galaxies can be considerably younger than a billion years.
I will briefly review the two main scenarios for dust formation,
Supernovae and AGB stars, and the constraints imposed by high redshift
observations on their typical timescales. I will then focus on the AGB 
scenario, which is particularly relevant also for our understanding of
the general evolution of these stars in the local Universe.
After a review of the dust contribution by stars of different mass and
metallicity, I will discuss some challenging problems found in the 
comparisons with observations, and their implications for population 
synthesis models with dust.