Barry Dunning operates a research program exploring the physics of atoms in highly-excited Rydberg states. While continuing to investigate the fundamental physical properties of these giant atoms, his group is also now using Rydberg atoms as a nanoscale laboratory in which to examine the manipulation and control of atomic wavefunctions, i.e., atomic engineering, and classical-quantum correspondence. Work using strontium Rydberg atoms is pushing towards formation of long-lived two-electron-excited “planetary atoms” whose behavior mimics that of a planetary system and the creation of Rydberg “molecules” comprising two neighboring Rydberg atoms. Dense ultra-cold gases are also being used to probe the formation of novel ultralong-range Rydberg molecules made up of a Rydberg atom and one, or more, ground state atoms weakly bound by scattering of the Rydberg electron. The appearance of many-body effects at very high densities, such as the creation of Rydberg polarons, is also being investigated. In other work, electron-molecule collisions at ultra-low electron energies and the properties of heavy-Rydberg ion-pair states are being studied.