Wit sparkles and burns.

Photo by Randy Tunnell: Beyond Words: Susan Forrest gives a tour de force performance as a dying intellectual.

Margaret Edson''s Wit, now at the Magic Circle Center, is as intellectually stimulating as it is emotionally touching, as analytically distant as it is personally immediate. It''s a star vehicle for the leading character, and a bully pulpit from which the playwright lambastes the medical profession and preaches the importance of kindness over smartness. At about an hour and 45 minutes with no intermission, it''s also long.

The play focuses on Professor Vivian Bearing''s final thoughts as she loses her battle to ovarian cancer. Expressed through a mixture of flashback scenes and direct addresses to the audience, we see how the crusty, independent scholar (specializing in the works of 17th-century metaphysical poet John Donne) is humbled and, in dying, made human.

There are many scenes depicting Bearing''s callous treatment at the hands of the doctors in the research hospital where she''s being treated. Therein lies the irony that propels Wit: Just as Bearing took an unemotional, unfeeling approach to her life and work, her doctors take the same approach to their work. Bearing is no more than a set of charts, a collection of specimens, an experiment dangling from monitors.

To say that Susan Forrest''s performance as Vivian Bearing is a tour de force may be an understatement. Her head shaved, wearing only a hospital gown and red baseball cap, Forrest must switch back and forth between the healthy, proud Bearing, and the one who is dying a slow, debilitating, and painful death. Not only does Forrest convincingly manage the shifts in body language from haughty to humbled, she is searingly intense in making the emotional and intellectual shifts. One of those shifts, in particular, was painfully jarring: In the midst of lecturing the audience on the meaning of one of Donne''s "Holy Sonnets," she is interrupted by a nurse who demands Bearing go for an ultrasound examination. At first defiant, Forrest shows us her character forced to submit to the inevitable, to admit that she is no longer in charge of her life. Her performance is both haunting and harrowing.

Strong performances are also turned in by the supporting cast. As Harvey Kelekian, the physician in charge of Bearing''s hospital, Philip Pearce gives his character two layers. Yes, he''s insensitive to the human needs of his patient, but Pearce also allows us to sense that his character is just a man doing his job, nothing personal. The script is susceptible to a more heavy-handed approach that would have turned the character into a cartoon villain.

As Jason Posner, the young intern in charge of Bearing''s case, Greg Falge shows us an ambitious young man bent on pursuing a career in medicine who sees patients only as a necessary evil. A former student of Bearing''s, Falge shows some of his character''s strongest moments as he wrestles with his uncomfortable feelings toward treating the former dragon of the English department.

As the nurse-with-a-heart-of-gold, Sherry Kefalas is so warm and caring that we can believe her final, violent confrontation with Posner, in defense of Bearing''s wishes. And Jennifer Forbes'' two scenes as Bearing''s former mentor are delightful: Logic be damned, her arch performance in the first scene and lovingly human performance in the second are both well done.

Kudos should go to director Elsa Con for choosing this challenging work, and for crafting a production that delivers Edson''s message without bludgeoning us with it. The uniformly top-notch performances by her cast speak to the thoroughness of Con''s attention to character development, the pacing of the show is almost relentless, and movement keeps us visually interested.

Wit continues at the Magic Circle Center through May 25.