In "Book of Days," Lanford Wilson proves he is not much of a mystery writer, pounds out social commentary with the finesse of a sledgehammer-wielding churl and isn't disciplined enough to choose a message and fully explore it before wandering into something new. But the Pulitzer Prize-winning playwright also weaves three stories into a seamless narrative, puts entertainingly ironic dialogue into the mouths of his characters and artfully shifts moods from light to dark.

Now onstage in a credible production from Montgomery Playhouse, "Book of Days" is not nearly as fully realized and rewarding as Wilson's "Prelude to a Kiss," "Talley's Folly" and "Fifth of July," all performed recently by Silver Spring Stage, or the fascinating "Master Class," but it remains passably watchable.

Wilson apparently has a bone to pick with the so-called religious right, which he sees as hypocritical and mean-spirited. But in "Book of Days," Wilson lets his anger control him, setting up one-dimensional villains and spending the rest of his play knocking them down. He ends up preaching only to that small part of the choir still paying attention by the time the story grinds to a halt.

He also allows lapses in common sense in order to pound away at his targets. Is it reasonable to expect, in a play grounded in lyrical realism, that a far-right, ostensibly pious Christian candidate for public office could jettison his wife after his girlfriend becomes pregnant, remarry and still command the support of his followers?

Wilson borrows Grover's Corners from Thornton Wilder's "Our Town," refashions it into contemporary Dublin, Mo., and begins with a nostalgia-steeped celebration of small-town America. We meet the colorful townsfolk as they constitute a choral ensemble describing the town and their lives, much as Wilder's Stage Manager does. As the trio of plotlines begins to form in a series of vignettes, each marked by the announcing of the date (hence the title), the choral contrivance occasionally reemerges to fill us in on back stories or offer commentary. And like "Our Town," "Book of Days" is staged in a stark, mostly unadorned setting.

Wilson opens up a number of interesting topics, such as the conflict between the corporate, bottom-line mentality and one man's quest for excellence, as played out in a cheese factory. A local theater group begins a production of George Bernard Shaw's "Saint Joan," which sets up several amusing story lines, with a fading big-time director forced into the hinterlands to escape scandal and a bookkeeper-actress who begins to live the part of the obsessed Joan.

With Wilson engrossed in sociopolitical commentary, the mystery plot never gets beyond the flimsy stage. It does, however, allow Andrea Spitz, as bookkeeper-actress Ruth Hoch, to delve deeply into her role and play it to perfection, dominating the show. As Ruth becomes something of a Saint Joan in Dublin, trying unsuccessfully to alert the townspeople to evil in their midst, Spitz creates a thoroughly multi-dimensional, spirited character. Other actors light up in Spitz's presence, further animating each scene in which she appears.

Director Karen Fleming keeps it simple and mostly within the range of her 12-member cast's varying levels of talent. David Gorsline provides an interesting Vincent Price-like characterization as the cosmopolitan, erudite director. Andy Greenleaf is suitably idealistic and sunny as Ruth's husband, Len, who strives to make good cheese, and Jean Aviles is piquant as Len's mother, Martha, a onetime hippie who remains libertine beneath a thin veneer of small-town respectability. In that, Martha is much like this play.

"Book of Days," performed by the Montgomery Playhouse (www.potomacstages.com/MontPlay.htm), continues through Oct. 9 at Asbury Methodist Village. Performances are at 8 p.m. Friday and Saturday, 3 p.m. Sunday. Tickets are $12 at the door, $10 students and seniors. Information: 301-977-5751.

Andrea Spitz, as bookkeeper-actress Ruth Hoch, dominates the show. Here she confronts David Jones, playing Earl Hill.