Directors Camille Hardman and Gary Lane trace the evolution of “9 to 5” from risky project to box-office smash to inspirational cultural phenomenon.

Viewed with 20/20 hindsight, all of history appears inevitable simply because it went to the trouble of happening. More than four decades after it defied skeptics, entertained millions, and hit the No. 2 spot (just behind “The Empire Strikes Back”) on the list of top-grossing 1980 movies, green-lighting “9 to 5” might now appear to be one of those surefire, no-brainer decisions made by Hollywood brass with absolute certainty of striking box-office gold. It wasn’t, of course, and reminding us of just how dicey a proposition it really was back in the day is just one of the enlightening and amusing elements of “Still Working 9 to 5.”

Documentarians Camille Hardman and Gary Lane do a splendidly entertaining job of showing how the comedy came together, with Jane Fonda — then at the height of her star power with two Oscars under her belt — and producing partner Bruce Gilbert serving as the driving forces for a film originally envisioned as a socially conscious drama (not unlike Fonda’s “The China Syndrome”), then a jet-black comedy, and finally a lighter and brighter piece of work that nonetheless hit all the right notes while underscoring injustices in the workplace.

Still Working 9 to 5