Was the Russian Revolution necessary?
Whether the Russian Revolution -- and there was actually a series of revolts and revolutions from 1825 through 1917 -- was "necessary" is entirely a matter of perspective. If you were a member of Russia's upper class, then the revolutution that deposed the Romanov Dynasty was neither necessary nor inevitable. From an outsiders historically perspective, a Russian revolution was inevitable because the era of unquestioned rule by monarchs was ending around the world.
Russian history, dating to the era of Kievan Rus (9th to 13th Centuries), when the seat of Russian heritage and politics was in the city of what is today the capital of Ukraine, Kiev, is one long tale of misery and deprivation visited upon millions of peasants. The Romanov Dynasty, when the czars ruled, began in 1613 and was marked by imperial rule, repression of the peasantry, and frequent wars against outside invaders. In the midst of this environment, especially starting in the early 19th Century, revolutionary movements began to emerge with the goal of overthrowing czarist rule. While the czars' secret police, the Okhrana, was effective at detecting subversive elements, the tide of history was turning against the Romanovs. In the meantime, the elaboration of alternative theories of economics and the evolution of societies were being written by, among others, Karl Marx and Friederich Engels, which provided the philosophical foundation for the growth of a revolutionary movement that proved skilled at subterfuge and equalled the Okhrana in ruthlessness.
In 1905, a peaceful demonstration in St. Petersburg urging governmental reform -- not rebellion -- was met with a violent armed response by the czar's troops. While precise numbers of dead and wounded protestors are not available, the military's response galvanized public opinion against the czar, and demands grew from reform to overthrow of the government. The communists, a well-organized and highly-motivated faction, formed a political movement in direct opposition to czarist rule, which responded again with overwhelming violence against an increasingly wide-spread revolt.
The start of what became known as World War I provided the communist activists, mainly the faction known as the Bolsheviks, the opportunity to exploit growing disenchantment with the Romanovs. An already poor country was losing thousands of soldiers in a conflict the Bolshevik's successfully portrayed as waged solely for the benefit of the imperialists in the West and their own monarchy. A February 1917 revolution successfully ousted the czar, and replaced him with a Provisional Government led by Alexander Kerensky, a major political figure, who in turn was overthrown by the Bolsheviks in October.
To the extent the Russian Revolution was "necessary," it was in the inherent injustice of the Russian governing structure and the continued plight of a peasantry increasingly tired of enforced servitude. What was not necessary, however, was the subversion of the February revolution by the Bolsheviks, who imposed a totalitarian system that survived for over 70 years.