Grossman initially studied at the Moscow State University as a chemical engineer, and upon graduation, took a job at Stalino in Donets Basin. In 1930, he changed careers, beginning to write full-time and published a number of short stories and several novels. At the outbreak of the Second World War, he was engaged as a war correspondent by the Krasnaya Zvezda; writing first-hand accounts of the battles of Moscow, Stalingrad, Kursk, and Berlin. Grossman also has eyewitness reports of a Nazi extermination camp, next to the discovery of Treblinka. These are the earliest accounts of a Nazi death camp by a reporter.
In 1941, Grossman was exempt from military servant but instead became a war correspondent, and wrote novels (The People are Immortal) which were published in newspapers and came to be regarded as a legendary war hero. He also described Nazi cleansing in German occupied Ukraine and Poland, and the liberation by the Red Army of Nazi-German Treblink and Majdanek extermination camps. His article “The Hell of Treblinka” was used at the Nuremberg Trials as evidence for the prosecution. 1https://web.archive.org/web/20110514042159/http://lib.ru/PROZA/GROSSMAN/trebl.txt
Grossman participated in the assembly of the Black Book, a project of the Jewish Anti-Fascist Committee to document the crimes of the Holocaust. The post-war suppression of the black book by the soviet state shook Grossman to the core, beginning to question his loyalty to the Soviet Regime. First, the censors ordered changes in the text to conceal the specifically anti-Jewish character of the atrocities and to downplay the role of Ukranians who worked with the Nazis as police.