A very interesting book; parts of it are very moving. I found the explanation for the Terror in Ch. 8 quite persuasive (see * below). OTOH, it is really not necessary to publish 700 page books that consist mainly of repetitive examples. That's what footnotes and reference systems, after all, are for...
* Stalin was expecting war with the fascist powers, and believed (not without cause) that the Western powers were trying to divert Hitler "to the East". And he feared (as the Tsar had suffered in WWI) social revolution "in the rear". At the same time, he observed the failure of the Republicans in Spain, undone by infighting on the Left (Anarchist, Communists, Trotskyites) -- from which he concluded that only repression at home could maintain the unity necessary to fight the Germans.
Stalin did not, of coures, believe that all these many people were actually spies or enemies (by Figes' count, nearly 1.5 million were arrested, and over 700,000 shot, in 1937-1938 alone). But he believed that if one or two real enemies could be caught, it was worth shooting a hundred..., or a thousand innocent men and women. They were simply trying, as Kaganovich (who lived to the ripe old age of 98) put it in the 1980's, to "drain the swamp"; or as Molotov, as late as 1986: The Terror for Stalin was merely "an insurance policy".