Whether the light water reactor (LWR) has become commercially "successful" remains uncertain even today. Its ambiguous future has been dominated by developments and events unforeseen when commercialization began. Although several reactor demonstration projects were technologically successful, the construction and operation of small LWRs did not convince utilities that large plants had economic attractiveness. Optimistic cost projections fostered the early stages of commercial-scale construction; the outcomes proved almost disastrous for some investors. Fossil fuel price increases eventually restored competitiveness of LWRs, but critical problems occurred because the interactive roles of government, manufacturers and utilities were not clarified until late in the commercialization phase. One consequence of LWR experience has been a reluctance of industry and utilities to invest in apparently risky energy programs. Demonstrating that both cost and technical obstacles can be adequately anticipated seems essential to induce future industry support in efforts to develop new energy sources. A high level of government participation and subsidy seems inevitable.