The main cause of the Bolshevik Revolution in 1917 was widespread discontent with the existing provisional government and its failure to address pressing socioeconomic issues. Disappointment with ongoing World War I casualties, food shortages, and the lack of land reforms fueled public unrest. The Bolshevik Party, led by Vladimir Lenin, promised peace, land, and bread to the war-weary and starving population, rallying support from soldiers, workers, and peasants disillusioned with the status quo. The successful October Revolution led to the overthrow of the provisional government, marking the start of communist rule in Russia.