Few disasters can inspire more compassion for victims and families than those involving structural collapse. Video clips of children's bodies pulled from earthquake stricken cities and bombing sties tend to invoke tremendous grief and sorrow because of the totally unpredictable nature of the crisis and lack of even the slightest degree of negligence (such as with those who choose to ignore storm warnings). Heartbreaking stories of people buried alive for days provide a visceral and horrific perspective of some of greatest fears ever to be imagined by human beings. Current trends toward urban sprawl and increasing human discord dictates that structural collapse disasters will continue to present themselves at an alarming rate. The proliferation of domestic terrorism, HAZMAT and biological contaminants further complicates the matter further and presents a daunting problem set for Urban Search and Rescue (USAR) organizations around the world. This paper amplifies the case for robot assisted search and rescue that was first presented during the KNOBSAR project initiated at the Colorado School of Mines in 1995. It anticipates increasing technical development in mobile robot technologies and promotes their use for a wide variety of humanitarian assistance missions. Focus is placed on development of advanced robotic systems that are employed in a complementary tool-like fashion as opposed to traditional robotic approaches that portend to replace humans in hazardous tasks. Operational challenges for USAR are presented first, followed by a brief history of mobiles robot development. The paper then presents conformal robotics as a new design paradigm with emphasis on variable geometry and volumes. A section on robot perception follows with an initial attempt to characterize sensing in a volumetric manner. Collaborative rescue is then briefly discussed with an emphasis on marsupial operations and linked mobility. The paper concludes with an emphasis on Human Robot Interface (HRI) and a call for additional research in this exciting and all too important field.