by a long-term vision: development of systems that display intelligent behavior in the AI case, and development of systems that generate synthetic environments meant to resemble the real world in the VR case. Progress in both these fields is marked by a series of research breakthroughs or technological advances that move ever closer to these objectives.

Each case study concludes with a summary of themes or lessons regarding the innovation process and the government's essential role within it. Because they derive from the individual case studies, these lessons reflect the particular conditions that prevailed at the time described, such as the nascent state of the computing field and dominant styles of federal research management in past decades. The case studies themselves do not attempt to discuss the relevance of these lessons to the current policy environment or to provide guidance regarding future federal support for research in computing. That task is taken up instead in Chapter 5 of this report, which synthesizes the lessons from all the case studies and attempts to consider their more general applicability.