Helen Keller was deaf, blind and mute, but during her lifetime she was one of the most articulate women alive. Mark Twain compared her in importance to Napoleon, Homer and Shakespeare. Winston Churchill called her the “greatest woman of our age.” Her autobiography, “The Story of My Life,” was widely read and, until Keller’s death in 1968, was taught in many high schools across the country. Despite two centennial editions reissued this year (she wrote the book as a student at Radcliffe College in 1903), the work has more or less faded into obscurity. Most students now read “The Diary of Anne Frank” instead.

But the real-life victory parable of the Helen Keller-Annie Sullivan relationship has not disappeared entirely. William Gibson’s play “The Miracle Worker” still is regularly produced in high schools and regional venues such as Penobscot Theatre, where a heart-wrenching rendition runs through Nov. 23 at the Opera House.

Since Penobscot Theatre is making its comeback after funding problems only a few short months ago, it’s tempting to relegate “Miracle Worker” to the ranks of “easy sell” when it comes to the community. It could be that Mark Torres, who programmed the work, was riding the wave of the hoo-ha over the 100th anniversary of Keller’s book, not to mention countless media stories about her, including a major feature in the New Yorker in June. It could be that the popularity of “The Diary of Anne Frank” last year taught him a lesson about wide-scale interest in tear-jerker epics. (The cutaway house structure of “Miracle Worker” was designed by Greg Mitchell, who also created the set for “Anne Frank.”)

But the production, directed by Don Jordan, stands on its own as worthy and rich. While Keller was criticized in her lifetime as a counterfeit and plagiarist, Gibson’s theatricalization lacks nothing in the way of emotional power, and that is Jordan’s great asset in a production that takes us to rural Alabama in the late 1880s, where the Keller household is tyrannized by the feral Helen whose whims are indulged out of pity for her handicaps. Every moment in the play leads to the now-famous scene at the water pump where Helen makes the connection between the wet substance pouring from the spigot and the signs of w-a-t-e-r that her teacher frantically spells into her palm.

“Somehow the mystery of language was revealed to me,” Helen wrote in her autobiography. “I knew that w-a-t-e-r meant the wonderful cool thing that was flowing over my hand. That living word awakened my soul.”

Actors Kae Cooney, as Annie, and John Bapst junior Elizabeth Lutz, as Helen, capture every nuance of that moment, which they achieve only because they have worked so scrupulously for the first two-plus hours to gain the trust of the audience. Their performances are engrossingly humorous, suspenseful and believable. It would be helpful if Cooney – as well as nearly all her onstage colleagues – would consistently speak up and enunciate, and if Lutz could let go fully when she throws her floor tantrums. But the two prove you don’t need eyes or ears for the reaches of determination, faith and love.

The show gets off to a slow start but picks up when Cooney’s Annie shows up at the Keller household, where family tensions are convincingly depicted by Pamela Rogers as Helen’s mother, Alex Cherington as her father, James Bocock as her half-brother, and Maggie McKee as Aunt Ev. Assata Sherrill, as Viney the house servant, stands out in a comic role that, nevertheless, underscores the post-war, middle-class, Southern, white household in which this play is set. (Helen, perhaps compelled by both her sensory struggles and her upbringing, would later become a socialist who fought for the rights of blacks, women and the underclass.)

The only real chink in the show, whose other cast members adequately play supporting roles, comes in the form of ghoulish shadows that lumber onto stage occasionally to represent Annie’s impoverished past. In an otherwise streamlined production, these haunting images are maudlin and interruptive – as if a few characters from “A Christmas Carol” pop in from time to time.

Lynne Chase’s lighting design evokes Southern moods as well as internal epiphanies, and Susan R. Smith’s costumes lend authenticity, as well as beauty, to the earthy tones of the scenery.

A bit of background: “The Miracle Worker” was first a teleplay in 1957, then a 1959 Broadway play that won a Tony Award for best play in 1960, and finally a 1962 movie for which Anne Bancroft and Patty Duke won Oscars. A Broadway-bound production with a $2 million budget and Hilary Swank as Annie Sullivan was mounted earlier this year in North Carolina, and would have been the first revival in 40 years but was canceled before the New York engagement. Gibson, whose biography is incorrect in the Penobscot Theatre program, was born in 1914 and, while he is best known for this play, he has won praise for his current Broadway hit “Golda’s Balcony,” about Israel’s former Prime Minister Golda Meir.

Finally, the resounding effect of the Penobscot production is: “The Miracle Worker” still is an important story that, when it works, will leave w-a-t-e-r streaming down your cheeks.

Penobscot Theatre will present “The Miracle Worker” through Nov. 23 at the Opera House on Main Street in Bangor. For information about tickets and special student matinees and outreach programs, call 942-3333. Alicia Anstead reviews theater for the Bangor Daily News. She can be reached at aanstead@bangordailynews.net.