Dame Stella Rimington: No stranger to controversy
The first female head of the secret service, she was also the first to be officially named and photographed during her tenure in charge of Britain's spy service.
Dame Stella, 65, was director-general of the internal security service from 1992 to 1996.
She was dubbed the "housewife spy" by some in the tabloid press after MI5's decision to name but not supply a picture of its new director-general.
She said of this: "That terrible snap, I'd always warned my daughter not to open the front door until she had checked who it was, but she forgot and called me down.
"There was a flash - which was actually quite worrying in my position, because you're never sure whether someone is trying to take your picture or shoot you."
Describing her time in office ahead of her book launch, she said in a statement: "I was fortunate to be in a central position during a time of great change in the security scene and I believe I have a contribution to make to our understanding of the period."
She describes her account as a "personal" memoir.
Establishment opposition
Her decision to publish caused concern in parliament, coming at the same time as the return of ex-agent David Shayler to face trial on charges of breaking the Official Secrets Act.
She is said to have been opposed by her successor at MI5, Sir Stephen Lander, and by the head of MI6, Sir Richard Dearlove.
The former Chief of Defence Staff, General Sir Charles Guthrie, has also strongly criticised her attempt to publish.
But after she reportedly threatened to invoke her right to freedom of expression under the Human Rights Act, ministers and officials are said to have concluded they could not block publication.
Dame Stella used some of her many years of high-level national security experience to good use when she left MI5 by becoming a non-executive director of Marks & Spencer.
Eavesdropping on customers
In a novel use of her surveillance skills, she walked around shop floors in an attempt to listen to what customers had to say about products and services before reporting back to her new bosses.
"She is interested in hearing what customers are saying and her eavesdropping is a first-hand way of getting some feedback," an M&S spokesman explained at the time.
In her post-MI5 life, Dame Stella also accepted non-executive directorships at British Gas and at a head-hunting company.
The most recent James Bond films have seen the fictitious supercool spy's boss portrayed by a female "M", with Dame Judi Dench filling that role.
Dame Stella said she found her portrayal as "startling", and added that it was "really very good. Both my daughters said so. One even noted that she holds her hands the way I do."