I. Direct Imaging of Circumstellar Disks

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o In the past five years, bservati ns at ptical and near-infrared wavelengths btained with the and gr und-based adaptive ptics have pr vided the first well-res lved images f y ung circumstellar disks, which may f rm planetary systems. We review these tw bservati nal techniques and highlight their results by presenting pr t type examples f disks imaged in the Taurus-Auriga and Ori n star-f rming regi ns. As appr priate, we discuss the disk parameters that may be typically derived fr m the bservati ns as well as the implicati ns that the bservati ns may have n ur understanding f, f r example, the r le f the ambient envir nment in shaping the disk ev luti n. We end with a brief summary f the pr spects f r future impr vements in spaceand gr und-based ptical/IR imaging techniques, and what impact they may have n disk studies.