Who really deserves credit for quantum gravity's most famous equation?

The Wheeler-DeWitt equation is the cornerstone of canonical quantum gravity, yet its credit has always been murky. This historical investigation, drawing on archives and published records from 1962–67, argues the decisive step wasn't stating the equation but defining its inner product — the mathematical structure that made calculation possible. It's a case study in how physics 'rigour' is really about enabling concrete results, not achieving abstract purity.