The work is a review of the book by a well-known British political scientist and historian Archie Brown «Seven Years That Changed the World» issued lately by the Oxford University Press and having for its subject analysis of the political history of the USSR of 1985 to 1991. According to Brown’s conception, the perestroika began as a reform, but shaped as systemic transformation, for it led to the change of all the key characteristics of the communist system. The main question the author of the book is concerned with is how did changes turn out possible in an extremely authoritarian system whose existence had lasted for about 70 years and which had more than once stood the trial of its durability? How did it happen that it proved at all possible to begin them - one would think, in defiance of «theory»? He sees the main reason that induced the beginning of the changes, in the «subjective factor», for in consolidated authoritarian systems, peaceful transformation can be started up only «from above». Therefore A.Brown’s attention is concentrated mainly on the activities of M.S.Gorbachev and other members of the top party leadership. At the same time he attaches great significance to the appearance in the power structures, as well as in expert institutions that assisted the party leadership, of people disposed in favour of changes.