Bayes’ Theory has been used to find a lost hydrogen bomb, break the German WWII code, identify smoking as a cause of lung cancer and heart disease, establish merit rating in insurance, and enable computers to “learn” and “make decisions.” But each time it was used, the techniques were not published, and the theory was allowed to die.  Actuaries played a prominent role throughout history in originally discovering Bayes’ Theory and resurrecting it to solve practical problems. Roy Goldman brings to life this actuarial history in his Contingencies article “Bayes’ Gift,” based on the book The Theory that would not Die by Sharon Bertsch McGrayne.