  I provide an overview about star-forming galaxies at high redshift and their
physical properties. Starting from the populations of Ly-$\alpha$ emitters and
Lyman break galaxies, I summarize their common features and distinction. Then I
summarize recent insight onto their physical properties gained from SED models
including nebular emission, and various implications from these studies on the
properties of star-formation at high redshift. Finally, I present new results
and an overview on the dust content and UV attenuation of $z>6$ galaxies
obtained from IRAM and ALMA observations.
