On Her Majesty's Secret Service is considered the second book in what is known as the "Blofeld trilogy", which begins with "Thunderball," continues with "On Her Majesty's Secret Service" after the interlude of "The Spy Who Loved Me," and concludes with "You Only Live Twice."
In 1969 it was adapted as the sixth film in the EON Productions James Bond series and was the first and only film to star George Lazenby as British Secret Service agent Commander James Bond. The film was also the second of three to portray Dr. Blofeld as the main villain; however, the films were in a difference sequence, beginning with "You Only Live Twice," continuing with "On Her Majesty's Secret Service," and concluding with "Diamonds Are Forever." This "trilogy" is significant not only for the three different Blofeld actors (Donald Pleasence - "You Only Live Twice" 1967; Telly Savalas - "On Her Majesty's Secret Service" 1969; and Charles Gray - "Diamonds Are Forever 1971"), but also exhibits two separate Bond actors (Sean Connery - "You Only Live Twice" 1967; George Lazenby - "On Her Majesty's Secret Service" 1969; and back to Sean Connery - "Diamonds Are Forever 1971").
For more than a year, James Bond, British secret agent 007, has been trailing the private criminal organization SPECTRE and its leader, Ernst Stavro Blofeld, in 'Operation Bedlam'. This pursuit is partially described in The Spy Who Loved Me, where Bond explains to Vivienne Michel the aftermath of 'Operation Thunderball' and the escape of Blofeld. By the time of On Her Majesty's Secret Service, Bond is convinced SPECTRE no longer exists. Frustrated by his inability to find Blofeld, Bond composes a letter of resignation for M. Meanwhile, Bond encounters a suicidal, beautiful, young woman named Teresa di Vicenzo and interrupts her attempted drowning. He and the woman are then captured by professional henchman.
They are taken to Marc-Ange Draco, head of the Unione Corse, the biggest European crime syndicate. Contessa Teresa di Vicenzo ('Tracy' to her friends) is the daughter and only child of Draco. Draco believes the only way to save his daughter is for Bond to marry her. To facilitate this, he offers Bond a great dowry; Bond refuses the offer, but agrees to continue romancing Tracy while her mental health improves.
Afterwards, in answer to a question, Draco uses his contact to quickly inform Bond that Blofeld is in Switzerland, but does not know precisely where. Bond returns to England only to be given another lead: the London College of Arms has discovered that one Ernst Stavro Blofeld has assumed the title and name Comte Balthazar de Bleuville, and wants formal confirmation of the title. Blofeld has undergone plastic surgery to physically pass as heir of the de Bleuville bloodline—- to the degree that he has asked the College to declare him the reigning count.
On a visit to the College of Arms, Bond finds that the family motto of Sir Thomas Bond is 'The World Is Not Enough', and that he might be (though unlikely) ancestor of Bond. Impersonating a College of Arms representative, Sir Hilary Bray, Bond is able to infiltrate Blofeld's lair atop Piz Gloria, where he finally meets Blofeld.
At Piz Gloria, Bond learns Blofeld has been curing a group of young British and Irish women of their livestock and food allergies. In truth, Blofeld and his homely aide, Irma Bunt, have been brainwashing them into carrying biological warfare agents back to Britain and Ireland in order to destroy Britain's agriculture economy, upon which post-World War II Britain depends.
Believing himself discovered, Bond escapes by ski from Piz Gloria and encounters Tracy, who is in town at the base of the mountain after being provided further information about Blofeld by her father and told that Bond may be in the vicinity. Tracy helps the exhausted Bond escape a carful of SPECTRE killers. Smitten by the resourceful, headstrong woman, he proposes marriage, and she accepts. Bond then returns to England and works on the plan to capture Blofeld.
Helped by Draco's Union Corse, Bond mounts an air assault against the clinic and Blofeld. Blofeld escapes down a bobsled run, tossing a grenade after the pursuing Bond, who narrowly misses being killed. Blofeld, however, escapes. He later avenges himself on James and Tracy Bond by killing Tracy in a drive-by shooting, shortly after their wedding.
Ian Fleming's 1963 novel was adapted as a daily comic strip published in the British Daily Express newspaper, and syndicated worldwide. Possibly the longest James Bond novel adaptation, the strip ran for nearly a year, from June 29, 1964 to May 17, 1965. The adaptation, which revived the comic strip after a two-year hiatus, was written by Henry Gammidge and illustrated by John McLusky; it was reprinted by Titan Books in 2004.