Wondering why Victor Serge is not recognized as a major writer

Victor Serge's novel Unforgiving Years (written 1946, published 1971) is a terrific novel start to finish - a fantastic and upsetting depiction of the years of World War II in 4 stages: First, in Paris just before the start of the war as two Russian espionage agents try to "resign" and to escape from Europe ahead of the Stalinist agents who will try to assassinate them; second, in Leningrad during the war, surrounded by German troops and a site of freezing and poverty, which we see through the eyes of a Russian agent/nurse; 3rd, in an unnamed German city in the final days of the war, scene of incredible poverty and danger and a scene of strangely mixed political alliances, heroism, and guilty; finally, Mexico, where the agents of the first chapter have established their redoubt, though they are still being pursued. There's so much in this novel - terrific topical descriptions, lots of intelligent discussion about the war and about espionage and political loyalties. The plot, no doubt, is difficult to follow at times, in part because it's not strictly linear and in part because all of the main characters use multiple names and aliases. But unlike much literary fiction, the plot builds to a conclusion and contains elements of tension and surprise right to the end. I'm not sure if this work, Serge's last, is typical of his (7) novels, but if it is it's amazing that he's so little known today - in large part, I think, because he's difficult to classify (he was born to a Russian-language family in exile, he wrote in French) and in part because his final 3 novels were never published in his lifetime, so that by the time they were published his day had come and gone. This novel is worth anyone's time and attention, and the intro from the translator, Richard Greeman, helps the reader navigate the complex plot of this novel.