P. Duff and Sons holds the title of "inventor of the cake mix".  right around the begining of the Great Depression, Mr. Duff's company found itself with a large molassess surplus.  He hit on the idea of dehydrating it and using it to create a "just add water" gingerbread mix.  and thus was invented the instant cake mix.  Cake mixes were more popular with Government Agencies (I.e. Military contracts)  than with consumers however, up through WWII.  The army and navy both immediatly recognized the value of dry foods in terms of logistics...being cheaper and easier to ship and keep from spoiling.  Seems most housewives didn't feel comfortable with instant cakes, however,  feeling like they were in some way "cheating" their family duties...  it took the post  WWII  advertising campaigns, the invention of canned frosting, and vigorously selling the idea that by decorating the cake at home, women were "making" it themselves and didn't need to be ashamed of taking the easy way out, so by the 60s the instant cake mix was an American institution.