A recent viewing of Alfred Hitchcock’s film is not a prerequisite, but it deepens one’s appreciation of “The 39 Steps,” which opened Sunday night, Aug. 16 at La Jolla Playhouse. The evolution of the stage work is extremely complex. Suffice it to say that this stage adaptation by Patrick Barlow is based on Simon Corble and Nobby Dimon’s original concept, which was based on John Buchan’s novel. Barlow’s adaptation is based more on the 1935 Hitchcock film than on the novel. Playgoers don’t really need to know that, either. To further complicate matters, the Playhouse production is shared with Seattle Repertory where it will play prior to the commencement of a separate national tour. Meanwhile, the much-nominated New York production continues at Broadway’s Helen Hayes Theatre, and the 2007 Laurence Olivier Award-winning London production also continues. Forget all that, and hie thee to the Playhouse for a ripping good time. The concept is that the 100-plus characters in the film are all played by three men and one woman. Ted Deasy portrays Richard Hannay, a lonely 37-year-old London bachelor who goes to the theater and becomes the target of an international spy ring when he harbors an opposing spy named Annabella (Claire Brownell), who is murdered by two men (Eric Hissom and Scott Parkinson). Brownell plays two other women in the story, a kindly farmer’s wife and the sophisticated blond, Pamela, who blows the whistle on Hannay not once but twice before discovering he’s not Annabella’s murderer. He is telling the truth about the sinister 39 Steps spy ring, which is trying to kill him and smuggle secrets out of the country. Hissom and Parkinson, sometimes in the twinkle of a hat, portray farmers, hoteliers, policemen and spies. Hissom’s portrayal of the Farmer is especially fetching. Both are excellent vocalists and dazzling physical comics. Young Bowman, a Montana native and a graduate of San Francisco’s American Conservatory Theatre, comes to this production direct from Broadway, where she understudied the female roles, having played in “The 39 Steps” at Huntington Theatre. Deasy assays the less dazzling but equally important role of Hannay, a fast thinker and long-distance runner who eludes the opposition repeatedly, at the 11th hour handcuffed to Pamela, with whom he falls in love. Barlow’s clever adaptation of all the others’ adaptations and of the film itself manages to include many other Hitchcock titles in the dialogue. Director of this magnificent display of actors’ gifts is the impressive Maria Aitken, a high comedy expert who staged the West End and Broadway productions of “The 39 Steps” and who has extensive credits in both the U.K. and U.S. as an actor, director and teacher. True to tradition, the production is staged to maximum effect with a minimum of accouterments: a few trunks, odd pieces of furniture, a lamp post, a lectern that becomes a drive shaft and human torsos that become the landscape of Scotland. Set and costumes are designed by Peter McKintosh, lighting design by Kevin Adams, and sound design by Mic [sic] Pool. “The 39 Steps” is wildly entertaining and an excellent addition to the Playhouse campus, where one may witness another brilliant sleight of hand in “Herringbone,” a one-man tour de force musical starring BD Wong as everyone. “The 39 Steps” continues in the Mandell Weiss Theatre, La Jolla Playhouse, through Sept. 13, with performances at 7:30 p.m. Tuesdays, Wednesdays and Sundays; 8 p.m. Thursdays through Saturdays; and 2 p.m. Saturdays and Sundays. For tickets ($30-$65), visit www.lajollaplayhouse.org or call (858) 550-1010.