weak neutral current In the 1960s, the emphasis in the study of the weak interaction shifted from strange particles to neutrinos. Leon Lederman, Steinberger and Schwartz built large spark chambers at Nevis Labs and exposed them in 1961 to neutrinos produced in association with muons in the decays of charged pions and kaons. They used the Alternating Gradient Synchrotron (AGS) at Brookhaven, and obtained a number of convincing events in which muons were produced, but no electrons. This result, for which they received the Nobel Prize in 1988, proved the existence of a type of neutrino associated with the muon, distinct from the neutrino produced in beta decay. Study of CP violation The CP violation (charge conjugation and parity) was established in the neutral kaon system in 1964. Steinberger recognized that the phenomenological parameter epsilon (ε) which quantifies the degree of CP violation could be measured in interference phenomena (See CP violation). In collaboration with Carlo Rubbia, he performed an experiment while on sabbatical at CERN during 1965 which demonstrated robustly the expected interference effect, and also measured precisely the difference in mass of the short-lived and long-lived neutral kaon masses. Back in the United States, Steinberger conducted an experiment at Brookhaven to observe CP violation in the semi-leptonic decays of neutral kaons. The charge asymmetry relates directly to the epsilon parameter, which was thereby measured precisely. This experiment also allowed the deduction of the phase of epsilon, and confirmed that CPT is a good symmetry of nature. CERN In 1968, Steinberger left Columbia University and accepted a position as a department director at CERN. He constructed an experiment there utilizing multi-wire proportional chambers (MWPC), recently invented by Georges Charpak. The MWPCs, augmented by micro-electronic amplifiers, allowed much larger samples of events to be recorded. Several results for neutral kaons were obtained and published in the early 1970s, including the observation of the rare decay of the neutral kaon to a muon pair, the time dependence of the asymmetry for semi-leptonic decays, and a more-precise measurement of the neutral kaon mass difference. A new era in experimental technique was opened. These new techniques proved crucial for the first demonstration of direct CP-violation. The NA31 experiment at CERN was built in the early 1980s using the CERN SPS 400 GeV proton synchrotron. As well as banks of MWPCs and a hadron calorimeter, it featured a liquid argon electromagnetic calorimeter with exceptional