The American Film Institute's Silver Theatre concludes its three-part series this year exploring the works of Alfred Hitchcock with one of the film auteur's finest works, 1959's North By Northwest, a mistaken-identity thriller that shows no signs of age. Cary Grant is terrific in the role of an ad exec mistaken by mobsters for a CIA operative. James Mason makes a deliciously suave villain, and there are some homoerotic undertones supplied by his main henchman, played by a very young Martin Landau. The film features two of Hitchcock's most famous set pieces -- a dazzling scuffle atop Mount Rushmore, and a seven-minute, wordless encounter between Grant and a rather hostile cropduster in a cornfield. Bernard Herrmann's score remains one of the most thrilling, memorable action-movie scores to this day. Saturday, Sept. 3, at 7:15 p.m., Sunday, Sept. 4, at 2:20 p.m., and Monday, Sept. 5, at 7 p.m. AFI Silver Theatre, 8633 Colesville Road, Silver Spring. Tickets are $11 for each screening. Call 301-495-6720 or visit afi.com/Silver.