Jonathan W. Rinzler is an author and editor for Lucas Licensing's book division. In that position I don't know how he got ahold of a rare blooper reel from the set of the first Star Wars film. He must have known the right people and been one of the few fortunate ones to get their hands on some cool memorabilia.
Thankfully he posted the blooper reel online and we can see some of the fun the cast had shooting the film. How things just went wrong for no reason and how when seeing a film from another angle. Things start to look very cheesy.