A vast literature devoted to Stalin has been produced. During Stalin's lifetime, his approved biographies were largely hagiographic in content. Stalin ensured that these works gave very little attention to his early life, particularly because he did not wish to emphasise his Georgian origins in a state numerically dominated by Russians. Since his death many more biographies have been written, although until the 1980s these relied largely on the same sources of information. Under Mikhail Gorbachev's Soviet administration various previously classified files on Stalin's life were made available to historians, at which point Stalin became "one of the most urgent and vital issues on the public agenda" in the Soviet Union. After the dissolution of the Union in 1991, the rest of the archives were opened to historians, resulting in much new information about Stalin coming to light, and producing a flood of new research.