Correction. The article on page 38 of the January 2011 issue of this magazine contains an error. The second sentence of the fifth paragraph stated that Albert Crewe was the physicist who first imaged single atoms. It was the late Erwin Müller and his student, Kanwar Bahadur, who first observed single, isolated atoms in the field ion microscope in 1956. The article should have read that Albert Crewe was “the physicist who first imaged single atoms in the electron microscope.”