"Hitchcock and Humor: a Study in Collaborative Authorship" presents three case studies that examine how Hitchcock's humor, a critical component of his touch, fluctuates and varies in accordance with his collaborators and his creative control. The first collaboration addressed involves Hitchcock's dealings with producer David O Selznick on both Rebecca (1940) and Spellbound (1945). By tracing each film through its initial treatments to its final screenplay, the each man's individual contribution comes to light and explains why Rebecca lacks the humor required for the full Hitchcock touch whereas Spellbound does provide comic moments. Under Selznick, Hitchcock first established a working relationship with actor Cary Grant. The two would continue to collaborate as the years went on and made four films together in all: Suspicion (1941), Notorious (1946), To Catch a Thief (1955), and North by Northwest (1959). In each subsequent film Hitchcock's methods of humor mesh more with Grant's screwball persona culminating in a Hitchcock classic full of funny moments. Along with Hitchcock's wit and Grant's physical comedy, North by Northwest owes a debt of gratitude to its screenwriter Ernest Lehman who created the original script simply out of sketches of characters and moments. The third case study examines the humor in Frenzy (1972). While Hitchcock's recent films had failed to reproduce the Hitchcock touch for an uncharacteristic lack of humor, Frenzy is laced with tongue-in-cheek action. The story was based on Arthur La Bern's novel Goodbye Piccadilly, Farewell Leicester Square (1972) and was adapted to the screen by playwright Anthony Shaffer to create what many call Hitchcock's return to form. These case studies reveal that the inclusion of humor in Hitchcock's films comes about when Hitchcock has the freedom away from the pressures of the studio and studio heads to assert his creative control with the collaborators and films of his choosing, preferably collaborators whose aesthetics compliment his own, and preferably films whose genre allows for generous tongue-in-cheek.