I've attempted to construct a chronology of the events depicted in the novels. Most of the novels 'happen' in the order that they were published but there are a few exceptions such as Snow Falcon and Firefox Down.

Emerald Decision and Moscow 5000 have been left out of the timeline as the characters from those books do not cross-over into what I call the 'Aubrey' novels.

The Publishers page contains a list of the novels in the order of publication.

1939 Aubrey meets the ten year old Brigitte. He helps her and her father escape Nazi Germany.
Revealed in All the Grey Cats. (Wildcat)
1940 The flashbacks from Jade Tiger. Aubrey is spying in wartime France.
Brigitte and her father arrive in America.
1943 Aubrey meets Brigitte in Washington. Her father is working on the Manhattan Project to build the Atomic bomb.
1944 Chapter one of Wolfsbane. Aubrey and Richard Gardiner are in France.
1946 Aubrey captured in the Russian section of Berlin as related in The Bear's Tears. (Lion's Run.) According the the forged Teardrop file this is the moment when he became a Russian spy.
1948 Brigitte's father is working at the Los Alamos laboratories and is approached about selling atomic secrets to Russia. Aubrey chases them through England. They bribe a pilot to get them to Berlin during the airlift. Aubrey kills Brigitte's father as they try to cross to the Soviet sector.
1955 Tim Gardner born.
1956 Brigitte Winterbach stationed at the East German Embassy in London. Aubrey beleves this is when Babbington was recruited by the East. Revealed in All the Grey Cats. (Wildcat)
1958 Winterbach and Babbington bribe the Chinese Lin to become a double agent in Malaysia during the Emergency. All the Grey Cats. (Wildcat)
1963 Wolfsbane, chapter two onwards. Aubrey becomes guardian to Tim Gardner and his brother.
1966 Richard Anderson betrayed by a superior.  He later moves to South Africa. Mentioned in A Hooded Crow.
197? USAF pilot Mitchell Gant shot down over Vietnam and captured by the Viet Cong.  This happens no later than 1973 as that was when the US forces pulled out of the conflict.
1975 The Events of Rat Trap. Approximately thirty years after World War II, which makes it roughly 1975.
1978 Patrick Hyde trained by the SAS. Tim Gardner joins the Gurkas.
1980 The Events of Firefox. No earlier than 1980, based on the documents printed at the start of the book. The 1968 Soviet invasion of Czechoslovakia was "twelve years ago" which fits.

The Events of Firefox Down. Immediately after Firefox. SAS man Alan Waterford is still alive at this point. RAF pilot Eastoe has worked for Aubrey before, perhaps referring to Sea Leopard.

1981 The Events of Sea Leopard. Admiral Dolohov is still alive.  Petrunin tries to kill Hyde in England.  Patrick Hyde's first appearance. (He drives a TR7 which dates this book!) The SIS must have recruited him after just a few years in the Army.
1982? The Events of Snow Falcon. Prior to 1983 as Yuri Andropov is still chairman of the KGB. He eventually became the Soviet leader in the real world. Waterford and Dolohov are both killed.  Buckholtz is still alive.
1982 The Events of Jade Tiger. Buckholtz is killed. Hyde remembers Petrunin from Sea Leopard, the events of which we are told happened 18 months previously.
1985? The Events of The Bear's Tears (Lion's Run). Aubrey becomes head of MI6. Hyde and Petrunin encounter each other for the last time. Russia still has forces in Afghanistan which must make it prior to 1989. My guess is about 1985 or 1986
1987 The Events of Winter Hawk. "18 months" after the events of Firefox which ain't gonna fit with Firefox happening in 1980!  Russian forces are still in Afghanistan and the Russian Space Shuttle is operational. (In the real world this would have to be 1988: The only flight of the Russian Space Shuttle, Buran [Snowstorm], took place that year.  The Soviet Union also pulled out of Afghanistan in 1989.)
1988 The Events of All the Grey Cats (Wildcat). "October". The events of The Bear's Tears took place less than a year before. Aubrey is recovering in England.  It is an election year in America so 1988 also seems to fit. The British Prime Minister is still a "she". The Berlin wall has not yet come down.
1990 The Events of The Last Raven. "November". The epilogue in the UK edition of All the Grey Cats places this book immediately after the previous book. This causes problems because in this book the Soviet Union has pulled out of Afghanistan, so it must be 1989 or 1990.
1991 Gant flies missions during "Desert Storm". (A Different War)
1992 The Events of A Hooded Crow. Perhaps one year later.  Aubrey resigns.  We discover that Hyde was once in the SAS.
1993 The Events of Playing With Cobras. Hyde has retired from MI6.  His last appearance until Slipping into Shadow. He moves to Australia with Ros, although Aubrey has a "job" for him.
1995 The Events of A Wild Justice. Alexei Vorontsyev (Snow Falcon) is no longer in Moscow working for the KGB. The Soviet Union is no more, so it must be the 1990s. The Bosnian conflict is continuing.
1997 The Events of A Different War. Sometime in the late-1990s.  Gant had served in the Gulf War. He is no longer in the USAF.  Enough time has elapsed for him to get married and divorced.
1998 The Events of Slipping into Shadow. Hyde has been living with Ros in Australia long enough for her to have set up her own company.   He is missing London and finally gets to do that "job" for Aubrey.  Hyde's army training was "twenty years ago". Reference is made to the 1998 Commonwealth Games which sets the book in that year.   Many references are made to Winterbourne and the events of A Different War.