Landmark contributions to science and mechanisms for the origin of the phenomena, and technology are rarely recognized at the time of reached important conclusions about the physical publication. Few people, even in technical areas, nature of the materials at equilibrium and their recogni zed the importance of developments such as electronic nonequilibrium properties. Many of these the transistor, the laser, or electrophotography ideas were condensed into a publication for Physical until well after their successful demonstration. Review Letters, paper 1 in this collection. This So-called experts, in fact, tend to resist new paper immediately attracted attention to the field, inventions, a natural instinct based on a combina and directly lead to the initiation of large research tion of fear of obsolescent expertise and jealousy efforts at both industrial laboratories and univer- arising from lack of active participation in the ties throughout the world. Inevitably, there was discovery. the usual amount of controversy, with many experts Denigration of new ideas is a relatively simultaneously taking positions (2) and (3) above. safe modus operandi, since the vast majority It has now been well over 20 years since eventually are abandoned well short of commerciality. the original publication date, and an objective view However, a successful device can be identified by can be taken in hindsight.