MI5: British Security Service Operations 1909-1945 (1981)
Matter of Trust: MI5, 1945-72 (1982)
The Circus: MI5 operations 1945-1972 (1983)
MI6: British Secret Intelligence Service Operations 1909-1945 (1983)
Unreliable Witness: Espionage Myths of the Second World War (1984)
A Thread of Deceit: Espionage Myths of World War II (1985)
Garbo: The Personal Story of the Most Successful Double Agent Ever (1985)
Operation Garbo: The Personal Story of the Most Successful Double Agent of World War Ii (1986)
GCHQ: The Secret Wireless War 1900-86 (1987)
Mole-Hunt: The Full Story of the Soviet Spy in MI5 (1987)
The Sigint Secrets: The Signals Intelligence War, 1900 to Today--including the Persecution of Gordon Welchman (1988)
Games of Intelligence: The Classified Conflict of International Espionage (1989)
The Friends: Britain's Post-war Secret Intellegence Operations (1990)
Seven Spies Who Changed the World (1991)
Secret War: The Story of SOE, Britain's Wartime Sabotage Organisation (1992)
The Illegals: The Double Lives of the Cold War's Most Secret Agents (1993)
The Faber Book of Espionage (1993)
The Faber Book of Treachery (1995)
Vietnam Book (1996)
Secret War for the Falklands: SAS, MI6 And the War Whitehall Nearly Lost (1997)
The Crown Jewels: The British Secrets At the Heart of the KGB Archives (1998) (with Oleg Tsarev)
Counterfeit Spies: Genuine Or Bogus? (1998)
British Security Co-Ordination: The Secret History of British Intelligence in the Americas 1940-45 (1998)
Secret History of British Intelligence in the Americas, 1940-45 (1998)
Venona: The Greatest Secret of the Cold War (1999)
The Third Secret: The CIA, Solidarity And the KGB's Plan to Kill the Pope (2000)
Triplex (2004) (with Oleg Tsarev)
Mortal Crimes: The Greatest Theft in History - Soviet Penetration of the Manhattan Project (2004)
Mask: MI5's Penetration of the Communist Party of Great Britain (2005)
Historical Dictionary of World War II Intelligence (2007)
Historical Dictionary of Sexspionage (2009)
The Guy Liddell Diaries, Volume I (2009)
The A to Z of British Intelligence (2009)
The A to Z of Sexspionage (2009)
Historical Dictionary of Ian Fleming's World of Intelligence (2009) (see Ian Fleming)
Historical Dictionary of Naval Intelligence (2010)
Snow: The astonishing story of the first double-cross agent (2011) (with Madoc Roberts)
Historical Dictionary of Chinese Intelligence (2012)