NEW YORK (AP) ― Over the past two years, publishers have been steadily filling one of the largest gaps in the e-book catalogue ― poetry.

Adrienne Rich, Allen Ginsberg, Langston Hughes and Wallace Stevens have been among the poets whose work recently became available in electronic format. And Random House Inc., W.W. Norton and several other publishers now routinely release new books in both print and digital versions, including last month’s Pulitzer Prize winner for poetry, Sharon Olds’ “Stag’s Leap.’’

“In the spring of 2010, we actually formed a team to focus on books that were complicated to make into e-books, like poetry and illustrated nonfiction,’’ says Liisa McCloy-Kelley, Random House Inc.’s vice president and director of e-book production, strategy and operations. “Over the past 20 months, we really shifted into production.’’

The problem had been how to transfer a poem from paper to screen without either breaking a line up ― a primal violation of the art form ― or making the font size too small to read. It’s unlikely that publishers can design a perfect solution, but they have managed to find acceptable compromises. In part, they credit advances in technology that make it easier to keep the original look intact. They also cite a technique long used in print.

The hanging indent.

The poet’s worst fear is for a line to break up randomly, ruining the rhythm and mood of the verse. But publishers and poets have been agreeable to ending the line at a specific word, then creating a second, indented line, alerting the reader that the train of thought belongs with the line above.

For instance, here are the first two lines of Olds’ poem “Love,’’ as they appear in the hardcover edition:

I had thought it was something we were in. I had thought we were/in it that day, in the capital

Here is how they look on an iPad 3:

I had thought it was something we were in. I had/thought we were/in it that day, in the capital

Poetry e-sales are a tiny subset of poetry sales, a perennial subset in publishing. But for publishers, and poets, it’s less about commerce than accessibility. Olds says she doesn’t have a lot of interest in e-books and has not seen the electronic edition of “Stag’s Leap,’’ but that she “certainly respected the fact that readers like to read in different ways.’’ Poet Philip Levine allowed such collections as the Pulitzer Prize-winning “The Simple Truth’’ to be digitized, even though he also has little personal interest in e-books.

“I don’t think the people who would buy an e-book of one of my books, or one of (W.S.) Merwin’s books would want it other than what it’s supposed to look like,’’ Levine said.

Part of the challenge is the devices themselves, with screens varying in size and feel from Apple’s iPad touchscreen to such smaller, standalone devices as Amazon.com’s Kindle and Barnes & Noble’s Nook. The e-book editions for Random House and other publishers will commonly include a reader’s note that suggests the proper font size for a given device.

Some works are especially challenging, like Anne Carson’s collection “Red Doc,’’ in which poems begins at various points on a given page. Random House decided on a fixed format, according to McCloy-Kelley, who says that the text “cannot be enlarged without a pinch and zoom,’’ meaning it can only be changed on a touchscreen. The verse of the late Greek poet C.P. Cavafy, who sometimes used extra spaces between words, proved so difficult to set accurately that English-language translator Daniel Mendelsohn settled for an e-book edition admittedly much different than what appeared on paper.