The first Soviet atomic bomb test, which took place at Semipalatinsk in Kazakhstan on 29 August 1949, was the most egregious test by far in terms of collective exposures to local fallout. This volume is devoted to this first, and to further nuclear weapon test explosions in the Semipalatinsk/Altai region. It analyses the environmental and human consequences of the radioactive fallout and presents detailed accounts, never published before in the West, of the methodologies of Russian scientists in source term analysis, dose reconstruction, and medical effects studies.