The Soviet defector and writer Victor Suvorov published a book in 1987 called Spetsnaz:  The Inside Story of the Soviet Special Forces.  Suvorov, whose real name is Vladimir Bogdanovich Rezun, was himself a Spetsnaz veteran and a Soviet intelligence officer.  I enjoyed his book Inside the Soviet Army as well; and he has written other volumes which I have not yet had the opportunity to examine.