Influential film director. He directed Psycho and NorthByNorthwest amongst others.
Hidden away in each of his films is a cameo appearance. He may be seen in a group picture, walking past in the streets, winding a clock... Usually when the scene is busy. Leads to a great game of Find the Hitch.
Have a look at ...
http://us.imdb.com/Name?Hitchcock,+Alfred
A lot of his movies employed a device called a McGuffin (or MacGuffin) which is simply something that moves the plot along, but has no meaning other than that.