"The Book of Nora" received unanimous acclaim from critics, who praised Carrie Coon's central performance, Leder's direction, and the emotionally and thematically resonant conclusion of the series.
Nora gives a recorded testimonial consenting to be part of Dr. Eden and Dr. Bekker's experiment to replicate the Departure, having tracked down the scientists and forced them to accept her as a test subject after previously being rejected.
She spends her days tending to birds that carry handwritten messages from the surrounding town back to the farm, and delivering them to a nun at a nearby church.
Kevin angrily confesses that he has spent his vacation time over the last several years relentlessly searching for Nora in Australia, refusing to believe that she truly departed.
"[2][3] The decision to set the finale ten years ahead of the series' main events was inspired by the Great Disappointment of 1844, which was used as a prominent metaphor for the third season and depicted onscreen in the opening scene of the premiere episode, "The Book of Kevin."
[2] Lindelof and writer Tom Spezialy both felt that Kevin's unnatural behavior would provide an appropriate counterpoint to Nora's pragmatism, and lend a "rom-com" air to their reunion.
[2] In the final scene of the episode, Nora explains to Kevin that the scientists' machine transported her to an alternate reality populated only by the departed individuals, and that she returned to the real world after seeing her family living happily.
Lindelof and the writers were particularly insistent on maintaining ambiguity over whether Nora's story is true, which informed the decision not to show onscreen flashbacks of her journey.
"[5] However, Lindelof did confirm that the writers had privately reached a verdict on the veracity of Nora's story, which he plans not to reveal in order to preserve the series' thematic coherence.
[2] The final scene shot for the series was Nora's entry into the LADR machine, whose design was derived from images of antique fusion reactors as well as the Large Hadron Collider.
The scene, which depicts a fully nude Nora, was filmed behind a closed set on a soundstage in Melbourne that was superheated to ensure Coon's comfort.
Leder, Coon and Lindelof experimented with various iterations of the scene's ending, ultimately deciding that Nora should ambiguously scream out at the last second before the episode cuts away to the farmhouse.
Lindelof and Spezialy contributed significantly to the editing process for the scene, swapping out a traditional musical score for archival audio and footage from the departure of Nora's family[2] The episode's title sequence reuses "Let the Mystery Be" by Iris DeMent, which served as the opening theme for the entirety of the second season.
Fowler appreciated the ambiguity of the final scene, suggesting that it invited a "fascinating mini-debate (...) that works to actually draw you into the story more intimately," and praised the "heartwarming" nature of the reunion between Kevin and Nora.
Club gave the episode an A, writing, "this is a finale likely to satisfy even those with the most stringent standards, those who have been nervous about how a show as broad and far-reaching as this one could possibly conclude in an appropriate way.
Alston particularly praised the episode's small scale and intimate focus on Kevin and Nora's romance, referring to the final scene between the two characters as "one of the most moving and devastating minutes of television" he could remember.
Or we can recognize that The Leftovers never promised any — that, both within the narrative and throughout Lindelof's publicity for the show over the years, it could not have been more clear that answers to metaphysical questions were besides the point."
Sepinwall reserved praise for Coon's performance, referring to the episode as "an hour of watching the hardest working woman in show business display all the range and raw power that gradually made Nora the most important person in the series' world.
"[9] Sean T. Collins of Vulture gave the finale 5 out of 5 stars, commending the episode for conveying Nora's fate strictly through Coon's monologue.
Sophie Gilbert, who co-authored the review, reacted positively to the episode's suggestion of an alternate reality populated by the departed, calling it "a surprisingly elegant and plausible way to conclude such a remarkable work of television.
Murray was similarly positive about the episode's austere focus on Kevin and Nora, applauding Lindelof and the writers for "cleverly [using] that relationship to round out The Leftovers without delivering anything too on-the-nose or overly explanatory.