After the Russian Revolution of 1917, Russian literature split into Soviet and white émigré parts. In the 1930s, Socialist realism became the predominant trend in Russia. Its leading figure was Maxim Gorky, who laid the foundations of this style. Mikhail Bulgakov was one of the leading writers of the Soviet era. Nikolay Ostrovsky's novel How the Steel Was Tempered has been among the most successful works of Russian literature. Various émigré writers, such as novelist Vladimir Nabokov continued to write in exile. Some writers dared to oppose Soviet ideology, such as Nobel Prize-winning novelist Aleksandr Solzhenitsyn, who wrote about life in the gulag camps.