The director and producer Alfred Hitchcock popularized the term “MacGuffin” and the technique with his 1935 film The 39 Steps, an early example of the concept. Hitchcock explained the term “MacGuffin” in a 1939 lecture at Columbia University in New York:
It might be a Scottish name, taken from a story about two men on a train. One man says, ‘What’s that package up there in the baggage rack?’ And the other answers, ‘Oh, that’s a MacGuffin’. The first one asks, ‘What’s a MacGuffin?’ ‘Well,’ the other man says, ‘it’s an apparatus for trapping lions in the Scottish Highlands.’ The first man says, ‘But there are no lions in the Scottish Highlands,’ and the other one answers, ‘Well then, that’s no MacGuffin!’ So you see that a MacGuffin is actually nothing at all.
Interviewed in 1966 by François Truffaut, Hitchcock explained the term “MacGuffin” using the same story.
Hitchcock also said, “The MacGuffin is the thing that the spies are after but the audience don’t care.”