The Manxman (1929)

Hitchcock understood, in a way that few other filmmakers have, that the attraction of cinema is the way it allows us to look without being seen, to satisfy our curiosity about other people's lives. His films frequently concern the act of looking, often in a way that is obsessive or unhealthy - think of the wheelchair-bound James Stewart spying on his neighbours in Rear Window (1954), or Anthony Perkins as Norman Bates watching Janet Leigh undressing in Psycho (1960).

In Hitchcock's silent melodrama The Manxman (1929), lowly fisherman Pete leaves his village to make his fortune at sea, hoping to return and marry Kate. While he is away, however, rumours spread that he has been killed, and meanwhile Kate falls in love with Pete's best friend Philip. Pete returns unharmed to a joyous welcome from friends, and is keen to see his best friend and his soon-to-be bride. But Philip and Kate are torn by feelings of guilt and shame. The way Hitchcock shows the looks the three exchange - and avoid - says more about their complex relationships than dialogue ever could.

At other times, Hitchcock lets the audience see things his characters cannot. In Young and Innocent (1938), Erica and Old Will are searching for an unknown murderer, a 'blinking man', in a crowded dancehall. The camera swoops over the dancers and zooms in on the 'blacked up' drummer in the band. As it approaches, he starts to blink uncontrollably. It is, as critic Charles Barr has noted, as if the camera itself is forcing him to reveal his guilt.

In Blackmail, Hitchcock takes the camera behind the screen where Alice is undressing. This invasion of her space helps create the sense of threat that culminates in Alice stabbing the man who tries to assault her.