“Be again, be again. (Pause.) All that old misery. (Pause.) Once wasn’t enough for you.”

Those words from “Krapp’s Last Tape,” along with every other word that Samuel Beckett ever wrote for the stage, were heard at the Lincoln Center Festival in 1996, courtesy of Dublin’s Gate Theatre. Once apparently wasn’t enough, though, for festivalgoers, though, so the Gate has dug a little deeper into Beckett’s archives and offered up some new misery — along with joy, bafflement, perversity, and general cantankerousness — for this year’s festival.

Three adaptations of Beckett works originally written for other media are on hand, and while “Eh Joe” and “First Love” have received the lion’s share of press attention due to their star power (Liam Neeson and Ralph Fiennes, respectively), Barry McGovern’s “I’ll Go On” is by far the most ambitious. Mr. McGovern and his collaborator, Gerry Dukes, have radically condensed the three linked novels — “Molloy,” “Malone Dies,” and “The Unnameable” — that Beckett wrote during a feverish creative stretch shortly after World War II. “Waiting for Godot” also sprung from this fecund period, which the author referred to as “the siege in the room.”

The novels have settled firmly into also-ran status in America, where Beckett’s reputation is based almost exclusively on his plays. But European audiences have long cherished them, with their disintegrating narratives and hall-of-mirrors consciousness, and Mr. McGovern’s potent and blazingly theatrical adaptation offers a virtuosic precis of their slippery charms. Far less sprawling but almost as potent is the 30-minute TV play “Eh Joe,” which Atom Egoyan has dazzlingly reconceptualized as a stage-film hybrid for the completely silent — and utterly hypnotic — Liam Neeson. (“First Love,” based on a 1945 Beckett novella, began performances last night and will be reviewed later this week.)

In 1985, when Mr. McGovern’s “I’ll Go On” had its premiere, trusted Beckett associates and acolytes were allowed far greater leeway in tinkering with the canon. Since then, however, the estate’s restrictions have grown steadily unaccommodating, and so the existence of two new stage adaptations is a curious and welcome new chapter to his dazzling oeuvre. (“Eh Joe” was also seen last year at New York Theatre Workshop, in a fussy and distancing staging by JoAnne Akalaitis.)

Rather than make sense of the novels’ various narrators, with their bewilderingly similar names (Murphy, Molloy, Mercier, Moran) and their habit of collapsing into madness, Messrs. McGovern and Dukes have streamlined the narrative into the addled reminiscences of one dying old man desperate to dispel the “mortal tedium” of his remaining days. The first act is devoted entirely to “Molloy,” and the formidable “Unnameable” is broached with a bravura stream-of-consciousness coda in which Mr. McGovern spews Beckett’s incantatory snippets of confusion and perseverance (including the famous phrase “I can’t go on, I’ll go on”) with harrowing precision.

Until that staggering finale, the emphasis is very much on the novels’ quirkier, more inviting moments. You’ll hear plenty about Molloy’s increasingly obsessive (and amusing) attempts to make sure his 16 “sucking stones” each receive equal time in his mouth — the fantastically detailed description will ring a bell to anyone familiar with the micromanaged stage instructions in Beckett’s plays — but nothing about the murders that he and several of the other narrators have committed. James McConnell’s icicle-sharp lighting conjures everything from a sepulchral pallor to a vaudevillian spotlight, and the superb Mr. McGovern follows suit, lending his seasoned rasp and stiff-legged gait to Beckett’s kaleidoscopic array of emotions.

Unlike the narrator of “I’ll Go On,” who can enliven his dwindling hours at least momentarily with the memories of a run-in with a policeman or a forlorn dog owner, the guilt-ravaged wreck at the center of “Eh Joe” has no such inner resources. Left with just enough money (for now) to pay for a weekly tryst with a prostitute, Joe is subjected to a barrage of venomous memories by the disembodied voice of an abandoned lover (Penelope Wilton). With the exception of a brief flurry of action at the very beginning and an even briefer (and unnecessary) flourish at the very end, he remains silent and immobile throughout.

Mr. Neeson’s brutish physicality and deep-rooted (and distinctly Irish) strain of melancholy would appear to make him a natural Beckettian, and Mr. Egoyan’s film credentials (“The Sweet Hereafter,” “Exotica”) mark him as a deft anatomist of grief. All the same, audiences would be justified in a certain degree of skepticism regarding “Eh Joe.” Thirty minutes of theater for nearly $100? With most of it on a screen? And the guy doesn’t even talk?

But as captured cannily by Mr. Egoyan, who projects an uninterrupted shot of Mr. Neeson’s face on a proscenium-filling scrim with increasing intensity (as per Beckett’s explicit instructions from the TV production) while the actor sits sideways, Mr. Neeson conveys volumes about the loneliness and regret careening within “that penny-farthing hell you call your mind.” The juxtaposition of his impassive profile with the ever-expanding image of his face offers unexpected dissonances, and Ms. Wilton’s prerecorded soundtrack matches his intensity cadence for cadence, her “voice like flint glass” lapping against the inside of his skull with a deceptively lulling force.

While everything about Mr. McGovern juts, from his close-cropped hair to his pugnacious chin, Mr. Neeson’s Joe is a study in glorious decrepitude; with his thunderous brow and battle-seasoned profile, he looks like a heroic statue that has been left too close to the fire. Mr. McConnell’s lighting falls slightly above Mr. Neeson’s head, intermittently casting his eyes — the only things that move on Joe’s face, until that unfortunate final flourish — in shadow. These brief respites, however, merely whet the appetite for the turbulent stillness that inevitably follows. A very different siege is taking place in a very different room — and neither Joe nor his transfixed audience is spared.

Both until July 27 (Tenth Avenue, between 58th and 59th streets, 212-721-6500).