Title: Dispersal of Gas by Photoevaporation in Disks

Abstract: Protoplanetary disks are believed to lose their primordial gas on timescales less than $\sim 10^7$  years, before which 
planetary systems must form. This talk reviews the present state of theory and observations of photoevaporation due to high energy 
photons and discusses disk dispersal. Recent models of disk evolution that suggest a possible link between planet formation and 
disk dispersal will be described.