Richard F.W. Bader
One of Canada's most prominent theoretical chemists, specializing in molecular structure and reactivity.
Bader is widely known for extending quantum mechanics to open systems, with his group's Quantum Theory of Atoms in Molecules. His book Atoms in Molecules: A Quantum Theory (The International Series of Monographs on Chemistry, No 22) discusses quantification of the theory behind molecular bonding and structure, a theory which has been widely demonstrated experimentally.
Source: Dr. Bader's Atoms and Molecules website.