Filming was tumultuous. Cameron, an American, was unfamiliar with British film-industry traditions such as tea breaks which interrupted production for up to an hour each weekday; he was frustrated at losing hours of filming every week. In his book, "The Making of Aliens", J. W. Rinzler described Cameron coming onto the set as George Lucas had before him for "Star Wars" (1977), but Cameron was aggressive and certain of what he wanted, which irked the crew. If he wanted to modify a scene (such as its lighting) in accordance with his vision, he did not involve the unionized crew.