I'm currently reading the novel Indigo by Austrian author Clemens J. Setz. The novel tells the story of Clemens Setz, who, after studying mathematics and German, does an internship as mathematics tutor at the Helianau boarding school in the Austrian Bundesland Styria, a school for "Indigo children", whose presence makes those around them feel nausea, dizziness and headache. The author biography in the front of the book states that the author, Clemens J. Setz, born in Graz, Austria, after studying mathematics and German, worked as a mathematics tutor at the Proximity Awareness & Learning Center Helianau and is suffering from the long-term effects of the Indigo-contamination.
The truth is that the Helianau boarding school does not exist, and that the author Setz never did an internship in a school for indigo children and is not suffering from the after-effects of anything. But the whole book is a tapestry of fiction and fact, interwoven so masterfully, that without extensive research (or an uncommonly broad educational background) you won't be able to tell one from the other. There are many things in the book which I was surprised to find were actually true, and many I was irritated to find were untrue.
Quite obviously, the pretense that the book recounts factual events, is part of its concept. Also quite obviously, the author biography serves to affirm and substantiate that pretense by misusing the reader's expectation that an author biography presents the truth.
In the case of "Robert Galbraith's" The Cuckoo's Calling, while the author is not part of the perceptibly fictional story, "his" military background gives his fictional works the appearance of being based on real life experiences, similar to real-life intelligence officer Ian Fleming's tales of the fictional spy James Bond. An author who as experienced and knows what he writes about, even if it is fictionalized, is more attractive to many readers than an author how has no idea "what it is really like" and makes it all up. For the same reason, books are often published under pseudonyms with a different gender than that of the acutal writer, because readers often prefer to read about certain topics when they are written by a man or a women, believing that only men or women can really understand whatever the book is about.
The author's implicit (pseudonym gender) or stated biography is always a part of both the narrative and the marketing of the book, and carefully crafted. An author's biography, in other words, is a literary device.
The public image of public figures is largely made up or manipulated.
- Politicians hold doctorate degrees by questionable foreign universities or are being convicted of plagiarism. Degrees signify expertise to the voters, but take time and effort.
- George Clooney and other stars supposedly pay young women to play their spouses for some time so as to appear desirable to their target audience.
- Every job applicant tunes their curriculum vitae and pretends to have knowledge and experience that they don't have.
The truth is that you should not trust the biography of anyone. Usually the sham isn't so blatant, but a biography is always a part of the marketing of the autor as a brand (or the neighbor as being more financially successful). Distrust it, until you see proof.