Mikhail Gorbachev's program ofglasnostandperestroika—now in its fifth year—has wrought striking changes inside the Soviet Union, and even more spectacular metamorphoses outside its borders. Among the positive repercussions of the Gorbachev program on the international scene, we have seen major improvements in international scientific cooperation. In particle physics the improvement during the years of the Gorbachev de´tente appears less dramatic than it does in space science, for example. But that's largely because the opportunity to solidify East‐West cooperation in particle physics had been seized much earlier—during the Khrushchev de´tente of 1956–60, a time when this field, with its large and expensive accelerators, stood alone as the epitome of “big science.”