Singer-songwriter Melissa Manchester is best known for straight-ahead pop hits such as “Don’t Cry Out Loud” and “Midnight Blue.” But in this musical, penned with Chicago-bred playwright Jeffrey Sweet, she draws on a childhood influenced by classical music (she’s the daughter of a bassoonist in the Metropolitan Opera orchestra). Her lyrical, complex score for this intimate one-act recalls the art songs of such American modernist composers as Aaron Copland and Samuel Barber; listeners probably won’t leave the theater humming the tunes, but this sophisticated show is well worth the ear of an audience seeking an alternative to the shallow bombast of Jekyll & Hyde and Miss Saigon. The quirky but sentimental story, based on a novel by Bernice Rubens (also the basis for a Simone Signoret movie) and set in 1950s New England, concerns a most unusual triangle: a lonely, middle-aged woman named Amy, her polio-stricken brother Stan, and their prim neighbor Gwen. When Amy places a personal ad in a newspaper, Stan responds without realizing he’s writing to his sister. His erotically frank letters offer Amy an outlet for her own repressed passions; she assumes an alter ego, “Angela,” to continue the correspondence even as Stan and Gwen’s friendship quietly blossoms into love. This staged reading of the work, which has been somewhat revised since receiving mixed reviews in its New York premiere several seasons back, stars Cass Morgan (coauthor and original star of the country crowd pleaser Pump Boys and Dinettes) in the vocally demanding role of Amy and Second City alum Meagen Fay as a proper schoolteacher Amy hires to impersonate Angela when Stan insists on a face-to-face meeting. Local performers Roger Anderson, Bethe Austin, and Kevin Earley portray Stan, Gwen, and Amy’s long-ago flame Jimmy, a footloose band singer who continues to haunt Amy’s memories years after their brief encounter. Noted Broadway choreographer Patricia Birch (Grease, A Little Night Music) staged the New York premiere and directs this production. Theatre Building, 1225 W. Belmont, Chicago, 773-327-5252. July 29 and 30: Saturday, 7:30 PM; Sunday, 10 AM. $10.