Felshtinsky has authored a number of books on Russian history, including The Bolsheviks and the Left SRs (Paris, 1985), Towards a History of Our Isolation (London, 1988; Moscow, 1991), The Failure of the World Revolution (London, 1991; Moscow, 1992), Blowing up Russia (with Alexander Litvinenko), and The Age of Assassins (with Vladimir Pribylovsky).

According to Felshtinsky, the list of assassinations includes poisoning of Vladimir Lenin, Felix Dzerzhinsky, and Maksim Gorky by Genrikh Yagoda on orders from Joseph Stalin, murders of Mikhail Frunze, Vyacheslav Menzhinsky, and Leon Trotsky, and the poisoning of Stalin by associates of Lavrentiy Beria.

At that time, he became acquainted with Alexander Litvinenko, a lieutenant colonel of the Federal Security Service (FSB).

Until 2006, Felshtinsky continued working with Litvinenko on gathering additional materials documenting the FSB's involvement in the apartment house bombings of September 1999.

[5][6][7] According to the authors, the bombings were committed by the Russian Federal Security Service (FSB), as a false flag operation intended to justify the Second Chechen War.