A book or play in letters is not a new concept — see A.R. Guerney's 1989 play Love Letters as one popular example of the form, or Alice Walker's The Color Purple — but the epistolary form is rare and almost strange concept in our age of abbreviation, and immediate, electronic discourse. Leave it to playwright Sarah Ruhl (In the Next Room (the Vibrator Play), Dead Man's Cell Phone) to dust off the genre and present it with fresh, articulate power in the form of Dear Elizabeth, now having its West Coast premiere at Berkeley Rep.

The play takes its text from the collected letters written between poets Elizabeth Bishop and Robert Lowell throughout their lives, which were published in the 2008 book, Words In Air: The Complete Correspondence Between Elizabeth Bishop and Robert Lowell. Bishop and Lowell were unrequited lovers and lifelong friends who deeply admired each others' work. They met at a party in New York in 1947 and bonded immediately, and as their letters show, there was a brief moment between his marriages when Lowell considered proposing to her. But he never did. It's not entirely clear what, if any, physical contact ever passed between them, but their love for each other, and each others' words, is more than evident in their three decades of correspondence.

Ruhl's hands were partially tied by the estates of the two poets, which insisted that she not invent any words outside the actual correspondence, or the poetry. (She says in the program notes that she "love[s] those kind of challenges.") There is only a single moment where she strays from this, foreshadowing something Lowell himself later admits, by projecting a couple of thought "bubbles" on the back wall of the stage. Otherwise, she and director Les Waters have crafted a piece of theater in which we are allowed to see and hear each character's yearnings, joys, and sorrows, and occasionally watch them touch each other beyond space and time, between letters.

Dear Elizabeth resonates on a few levels. It is both a tale of lost love, and the endurance of friendship and attraction; and a glimpse into an age of written correspondence that is now long gone. It's bittersweet to learn how much passed between these people in the letters they wrote — personal triumphs and traumas, as well as sharp critiques of each others' work — and to realize how little of this kind of communication happens anymore. We are, perhaps, too connected to each other to need such investments of time and paper, and that, Ruhl implies, may be the greatest tragedy of all.

The performances by Mary Beth Fisher and Tom Nelis are restrained and just right, allowing us to hear both poets' rhythms and witticisms with believable life, and pathos.

Waters' direction, too, may be the source of that restraint, choosing to adhere to similar strictures as Ruhl had to. He places the characters primarily at a table beside each other, reading words, only infrequently acting out their dramas until the second act, when they spend much of their time on their feet — just as the people they're playing were spending most of their later lives apart. A few times, knocked down by life as they were, we find Bishop and Lowell laid flat out on the floor with their sadness, and in a particularly dramatic Waters-esque touch, there is an unexpected water effect that is both magical and moving, and used sparingly.

It's a play, to be sure, that will be most powerful to poetry fans, however few there are left. But nonetheless it's a powerful piece that would appeal to any romantic who's shed a tear over someone who got away.

Dear Elizabeth plays through July 7. Get tickets here, and note that if you're under the age of 30, you get a discount. Select 'Under 30' price when you're buying online.