This year x‐ray astronomy celebrates its silver anniversary. It was in 1962 that Riccardo Giacconi, Herbert Gursky, Frank Paolini and Bruno Rossi found x rays (from Scorpius X‐l) coming from outside the Solar System. Freeman Dyson in a talk given at Cornell in 1984 said: “The old quiescent universe of Aristotle, which had survived essentially intact the intellectual revolutions associated with the names of Copernicus, Newton and Einstein, disappeared forever as soon as the x‐ray telescopes went to work.” After years of rocket and balloon observations, the first x‐ray satellite, Uhuru (Swahili for “Freedom”), was launched in 1970 off the coast of Africa, accelerating the evolution of x‐ray astronomy. (See the figure on page 28.)

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