Why Hoffmann? The Person and the Young Chemical Physicist.

In 1965, R. B. Woodward and Roald Hoffmann published five communications that formed the basis of the Principle of Conservation of Orbital Symmetry which explained mechanisms of all pericyclic reactions and predicted the allowedness and forbiddeness of such reactions, whether thermal or photochemical. A brief biographical discussion of Hoffmann up to May 1964 is explains why Hoffmann was the ideal individual to participate in the collaboration with Woodward. Why May 1964? Because it was then that the Woodward-Hoffmann collaboration began.