After his return home, Dan spoke about his experiences in the book Unde începe noaptea ("Where Night Begins"), which endures one of the few Romanian contributions to Holocaust literature, and has for long been censored by dictatorial regimes.

Dan was eventually forced to adapt his writing style to the aesthetic requirements of Romanian Socialist realism, and spent the final decades of his life in relative obscurity.

[7] Dan and Dianu were also co-opted by Ion Vinea on his various journalistic ventures, beginning with the left-wing and modernist literary review Contimporanul, where they published avant-garde prose and poetry with a political subtext.

However, documents first made public in 2008 show that he was secretly an informant for the Kingdom of Romania's intelligence agency, Siguranța Statului, with a mission to supervise unu's ongoing flirtations with communism.

[10] Also in 1930, shortly after the forceful return of Romanian King Carol II to the throne, Sergiu Dan was working, as political editor,[3] on the staff of Dreptatea, the platform of the National Peasants' Party (PNȚ).

[12] Sergiu Dan's actual editorial debut came in 1931, when Editura Cugetarea published his novel Dragoste și moarte în provincie ("Love and Death in the Provinces").

[13] In 1932, Sergiu Dan joined the staff of Vinea's gazette Facla, with novelist Ion Călugăru, poet N. Davidescu, writer-director Sandu Eliad, and professional journalists Nicolae Carandino and Henric Streitman.

[22] The book, written as a response to early signs of Holocaust denial,[3] was reportedly taken out of circulation for unknown reasons; it was later suggested that it clashed with the Communist Party agenda, at a time when Romania was undergoing fast communization.

[28] Dan was eventually released around 1955, when, according to Zalis (a personal witness to the events, alongside novelist Zaharia Stancu), he confided to fellow members of the official Writers' Union about his time in prison.

[22] In 1970, Editura Minerva republished Roza și ceilalți and Arsenic, while Cartea Românească printed his last volume, Dintr-un jurnal de noapte ("From a Nightly Diary").

[3] His overall contribution also covers Romanian-language versions of works by Louis Aragon, Michel Droit, Maurice Druon, Anatole France, Boris Polevoy, Elsa Triolet and Voltaire.

[2] Those fragments published by Contimporanul in the 1920s have been included by researcher Paul Cernat in a special group of "iconoclastic" and absurdist short prose (with those of Dianu, F. Brunea-Fox, Filip Corsa or Sandu Tudor).

[29] His experimental prose fragment Rocambole was a parody of Pierre Alexis Ponson du Terrail's 19th century series (and of literary conventions in general): although only covering half a page, it carried the subtitle "grand adventure novel", and showed its eponymous anti-hero as an incestuous kleptomaniac.

[31] Cernat illustrates this conclusion with Dan's free verse "diary-poem", published in Issue 71 of Contimporanul, a sample of "cynical libertinism" and "absolute aesthetic freedom":

"[36] While the Anton Pann narrative earned appreciation for freely mixing picturesque elements into a historical novel framework, Dan's solo debut with Dragoste și moarte... takes direct inspiration from Gustave Flaubert.

[35] Arsenic received high praise from Crohmălniceanu: "The book is written with much confidence, it displays remarkable intellectual detachment, fine Voltairian irony and an ingenious, irreproachable, counterpoint construction.

"[38] In Surorile Veniamin, Dan's political novel, the narrative follows the symmetrical lives of two sisters: Felicia, who rejects social conformity and braves a life of poverty; and Maria, who works in the thriving oil industry and then becomes a kept woman.

The plot is complicated by Felicia's affair with agitator Mihai Vasiliu, a Romanian Communist Party member who is pursued by Siguranța Statului agents, and who hides in Maria's apartment.

[35] Crohmălniceanu believes the book displays qualities similar to Arsenic's, but notes that Vasiliu's ultimate arrest, which leaves both sisters unconsoled, leads the outcome into a "disappointingly inconsistent" solution.

[38] With Unde începe noaptea, Sergiu Dan spoke about his own experience as a victim of Nazism and of Ion Antonescu's regime, with additional detail on the January 1941 Pogrom.

[40] They describe Unde începe... as "a documentary novel about life in the concentration camp", one of the first-generation East-Central European books to deal with the World War II tragedy.

[41] This view is contrasted by poet and critic Boris Marian, who finds that the narrative, which displays "impressive realism" and "alert style", is not documentary, but rather personal; according to him, although briefly showing communists at work, Unde începe... goes against its time by not presenting them in an ideal light.

Called a "tragic buffoonery" by George Călinescu (in an updated version of his 1941 overview), the narrative culminates with the German retreat, after which Roza, branded a collaborator, is tortured and raped by her own community.

[11] However, giving in to political pressure after his return from jail, he produced Tase cel Mare: called an "accessible" and "simplistic" novel by Zalis,[11] it is thematically linked to the world depicted in Surorile Veniamin.

[46] Some other such exceptions are Camil Baltazar, Maria Banuș, Aurel Baranga, F. Brunea-Fox, Eusebiu Camilar, Georgeta Horodincă, Alexandru Ivasiuc, Norman Manea, Sașa Pană and Titus Popovici.

"[3] Henri Zalis took special care to republish and reevaluate the early work of Sergiu Dan and other Jewish Romanians, a conscious effort to reduce the impact of antisemitic or communist repression.