By Craig Kurtz
The fact remains that closing credits, as we know them today which listed everyone who did anything in the film, did not start being used until the late 60’s, and early 70’s. Opening credits might have been seen when talkies started but would only show major cast and crew, if anyone.   There were No Closing Credits.   
One reason for the lack of credits during the Celluloid time was it was expensive to dole out the names that most, if not all film-goers would not even see as they exited the theater as soon as they began running.   With the advent of Digital, the expense became less of an issue.   Another issue was the Big Studios wanted all the credit.  
However, we all know that EVERYONE is important from top to bottom to create a Film.    Each and every person involved in all the details DESERVES CREDIT.
And if you do look at the credits and are not involved in filmmaking, you may wonder what some of these jobs entail. Here’s a brief description:
Gaffer – Chief Lighting Tech
Best Boy – Lead Assistant assigned to Gaffer
Key Grip – Oversees the Grip Department which sets up the Lighting & Electrical Rigging
Dolly Grip – Specialized in Camera Dollies & Crane Shots
Film Unions controlled many rules for how Credits were handled in the business.
Screenwriter Credit – for motion pictures made under established state/federal laws governing business,  the Writers Guild of America is the final Arbitrator to decide who receives Screenplay Credit.  The Screenplay could be an original story or be adapted from a previous story or character.
So Who Else should get Credit?   YOU as a FILM-GOER are a big part as you complete the circle of filmmaking.  
So the next time you see a film, take some time to look at the credits and just how many people were involved in the production!!