![Collection image](http://cdn.journals.aps.org/test/8a3a9d1e-d338-42fc-a524-41aa9811239f/Key-Image.png)
50 Years of QCD
A new Collection by the Physical Review journals celebrates the 50th anniversary of the discovery of asymptotic freedom in quantum chromodynamics (QCD)—the theoretical basis for the strong force of nature that binds quarks and gluons into hadrons.