MOSCOW—Boris Berezovsky, the man who more than any other came to epitomize the oligarchs of 1990s Russia, died Saturday at a residence outside London, capping a life that saw the heights of power and wealth before witnessing diminished fortunes in exile.

Mr. Berezovsky, 67, was a former academic mathematician who developed into one of Russia's best-known tycoons in an era of privatization, violence and cutthroat capitalism that defined Russia after the collapse of the Soviet Union.

...