Last month, Melville House was making headlines for a French bestseller by a philosopher who claimed to have figured out the key to happiness. This month the Brooklyn-based indie has what it hopes is another French hit on its hands: an account of one of the biggest human exoduses in history, as millions fled Paris in 1940.

The book, 33 Days, which was released today, is Léon Werth's memoir about the mass migration. Dennis Johnson, founder of Melville House, said 33 Days offers a "day-by-day, minute-by-minute" report of the harrowing journey, and is one of the few eyewitness accounts of this largely overlooked moment in 20th century history.

Aside from the historical significance of the book--Melville House's edition of 33 Days marks the first time the text will be available in English--Johnson is also hoping people take note of the unusual circumstances in which the title was published.

Not released in France until 1992, the book was supposed to come out shortly after Werth and his family survived the grueling trek--fleeing the encroaching German army--from Paris to eastern France. One of the author's closest friends, Antoine de Saint-Exupéry (best known as the author of The Little Prince), took the manuscript with the intention of having the book published in the U.S.

According to Johnson, Saint-Exupéry traveled to the States in the early days of World War II, hoping to convince the Americans to join the fighting in Europe. Saint-Exupéry smuggled Werth's manuscript out of France and, in 1941, made an agreement to have the title published by Brentano's Bookstore, a former New York City bookstore-publisher that, at the time, was releasing books in French.

The agreement with Brentano's, however, fell through, and Werth's account never saw the light of day. Decades later, a French publisher--Viviane Hamy--found the manuscript and published the work to acclaim, and strong sales, in France.

Melville House found out about the book shortly after it was published in France, but Johnson wanted to release the title as it was initially intended, featuring an introduction by Saint-Exupéry. Hamy told Melville House that she thought the introduction no longer existed and Gallimard, the large French publisher that essentially represents the Saint-Exupéry estate, concurred, dismissing the notion that the introduction was somehow out there, waiting to be found.

Nonetheless, Melville House went looking. Johnson said the hunt was truly a group effort--among those helping out included a former French-speaking intern--and it bore fruit. The small publisher ultimately located the piece of writing in the Quebec National Archives, which Johnson credits to the fact that the author spent a few weeks one summer, around 1940, in Montreal.

Melville House's edition of Werth's memoir, featuring the original Saint-Exupéry introduction, is, according to Johnson, special on a number of levels. "It's not often you get to say I'm publishing a new piece of writing by Antoine de Saint-Exupéry," he said. Beyond that, Johnson believes the Saint-Exupéry piece shines a light on the bond the famous author shared with his lesser-known mentor. Saint-Exupéry dedicated The Little Prince to Werth, Johnson noted, and the introduction more fully displays "the touching friendship between these two guys."

Ultimately, though, Johnson hopes Werth's memoir, which the press is doing an announced 15,000-copy print run for, will offer Americans a window into an event seemingly forgotten by history. The nearly month-long trek Werth participated in, historians now believe, was made by eight million people. As Johnson put it: "It was news to me that this was [one of] the biggest human exoduses in history."

Correction: An earlier version of this article misstated the number of times Antoine de Saint-Exupéry traveled to America during WWII. He visited once, not multiple times. Additionally, this article originally stated that millions of Jews fled Paris in the 1940 exodus. Millions of people fled the city in the 1940 exodus, but they were not all Jewish.