Weinberg became Eugene Higgins Professor of Physics at Harvard University in 1973, a post he held until 1983. In 1979 he pioneered the modern view on the renormalization aspect of quantum field theory that considers all quantum field theories effective field theories and changed the viewpoint of previous work (including his own in his 1967 paper) that a sensible quantum field theory must be renormalizable. This approach allowed the development of effective theory of quantum gravity, low energy QCD, heavy quark effective field theory and other developments, and is a topic of considerable interest in current research.