2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/5958This review covers the properties of disks around pre-main--sequence stars. It is at this time in the evolution that planets form, and it is important to understand the properties of these disks to understand planet formation. I discuss disk shapes, masses and temperatures, the properties of the host stars, disk lifetimes and dissipation processes. Finally, evidence of grain growth during pre-main-sequence evolution is briefly summarized.In "Debris Disks and the Formation of Planets: a Symposium in Memory of Fred Gillett", Tucson, Apr.2002, D. Backman and L. Caroff Eds. ASP Conference Series, in pressAstrophysicstext