The third large number of works resulted from the official unmasking of Blunt in 1979. Finally, with the collapse of the Soviet Union, the 1990s have seen a number of books, some of which were based heavily on KGB files and the memoirs of former KGB agents. Each subsequent group of books reexamined the evidence from the previous group or groups, so that there has been a constant review and reinterpretation of the lives and work of the four principals. In many respects, the nationalities of the authors correlate with how Philby, et al , are treated. American authors tend to be unimpressed by the talents and accomplishments of the Cambridge spies, and are clearly not charmed by the elegance attributed to them.
English writers are more inclined to treat the four spies more kindly.
However extensive the literature on this case, Philby and Blunt remain inscrutable and unfathomable characters, while Burgess and Maclean seem weak and neurotic. The Crime Library particularly recommends three recent works. With the exception of the speculative early works, almost everything written since 1980 has merit, and should not be ignored by the serious student of this case. Bethell, Lord Nicholas. The Untold Story of Kim Philby's Biggest Coup.