I am a great observer of people, whether sitting in bars and cafes, or walking in the street, I am always looking at men, women and children and subconsciously making notes. I study not just what they're wearing, but also what they're trying to achieve. Are they being flashy or flirtatious, sober or sensible, casual or classy? I watch how they comport themselves. Are they hiding a pot belly, a bald head, a weak chin? How do others react to them? Do they turn heads? Are they an affront to other people? If someone particularly fascinates me I imagine the life they've lived or, more accurately, I give them a life to suit their look.

When it comes to writing I draw on these subconscious notes. They are rarely written down. The test is that if I have remembered them then they must have some importance. Quite often walk-on characters have assumed far greater roles in the story than I initially envisioned. A woman I may have seen in a cake shop and had conceived of as nouveau riche, materialistic, conservative, firmly embedded in her social class and concerned about her position in it, can be transformed by fiction. She may suddenly refuse to behave in the way in which I imagined. Once I've put her in a scene, say, the grieving widow being interviewed by the detective investigating her husband's murder, she may start to fight her way out of my fictional strait jacket. This is the wonder of being a writer; when characters assume life and take on an even greater reality.

Characters, like people, do not appear out of nowhere. First they have to belong somewhere. My first stop on the way to developing a character is to have the setting in mind. In my case I had decided that Seville in Spain would make a great setting for a crime novel. But why? Seville has one of the lowest murder rates in Spain, is recognized as one of the most beautiful cities in the world, with people who are amongst the most vivacious in Europe. And it was precisely for these reasons that I decided it would be the perfect setting for mayhem and murder.

One of the fundamental themes of crime fiction is: appearance and reality. What better place to set a crime novel than in a place which appears to be beautiful and full of attractive people, but which, like all cities, has a dark underbelly of crime, vice, drugs and racial tensions?

Even at this early stage there is a recognizable process. Characters are coming into being because I'm asking myself a series of questions. Their development, and that of the plot, will come from my answers to those questions. So because of the nature of my setting I decided that my detective hero was going to appear to be one sort of person, but in reality be someone completely different.

In The Blind Man of Seville, when we first come across the Spanish detective, Chief Inspector Javier Falcon, he is Mr. Straight. He is perfectly groomed in a suit which he wears buttoned up, a white shirt and tie and lace-up shoes. He is contained, some might say restrained. He is not liked by his colleagues, who find him cold and uncommunicative. They have given him the nickname of The Lizard. I began by creating a hero who was not instantly likeable. But what this gave me was the opportunity, in the course of the book, to change him.

Policemen are naturally conservative people, engaged in a profession with a hierarchy. In order to be a homicide detective you have to be a senior policeman and therefore middle-aged -- and middle-aged men do not change. They might tell a new joke (if you're lucky) or give up smoking or try out all the facial hair options, but they will not, fundamentally, change. So how could I change Javier Falcon? After some thought I realized that only a major psychological trauma was going to be able to wreak havoc (and therefore change) in the mind of such a person.

Our lives are built on the foundations of belonging. We have family who give us a sense of our place in the world. Rock those foundations and our world falls apart. This was what I did to Javier Falcon. In investigating a brutal murder in Seville he finds himself digging around in his own history. In doing so he uncovers some terrible truths about his own father and the way in which his beloved mother, who had died when he was only five years old, had met her end. They are shattering revelations. They break him as a human being and leave him hanging on to his new, terrible world by the thinnest of shreds.

This is another important part of character development -- the back story. Where does your character come from? Where was he born? Where did he grow up? What is his relationship to his parents, siblings, friends, colleagues and lovers? Where did he go to school? Did he go to university? What was the political climate like? Why did he choose his current profession?

The answers to these questions can help you determine a character's development, but what are the techniques that help you show these answers to your reader? Unless back story and the book's plot are interwoven the reader does not want to know it. The reader is only interested in what's happening now and what is going to happen.

There's a limit to how much you can show through action and reaction -- think how little you learn about people in everyday life from what they do and say, and I don't just mean politicians. People have a habit of being deceptive, to protect themselves from intrusion. They are not usually open, especially if they have something terrible to hide.

Opening up characters is a tricky process but I have found one of the more fascinating ways is to put them into a scene with difficult people and in trying circumstances so that they give themselves away. Conflict leads to drama, which leads to revelations.

Another way of demonstrating a character is showing him from a different point of view: A sister may see her brother as lovable. A brother sees him as dependable. A colleague values the same man because of his insight. A lover despises him for some reason. And of course, all these ancillary characters have their own personalities and our understanding of them gives us a different perception of the hero.

But how do we get into the deeply hidden stuff? I chose to put Javier Falcon on the psychologist's couch to reveal to him, and us, the bits that our hero doesn't know himself.

The irony of all this is that in finally understanding Javier, we see him broken and we reach another unknowable area: What does he have inside him so that he can rebuild himself? I had the advantage of rehabilitating my hero in a series of books. In The Vanished Hands he mends himself through communication with others. The gross intrusion of reality into his own life has given him a better understanding of the intrusiveness of investigative police work into other peoples' lives. It is for this reason that the plot and all the characters' stories come out almost entirely in dialogue. In the latest novel, The Hidden Assassins, Javier is in full command of his new talents and has become more intuitive, instinctive and human.

Perhaps, though, the ultimate secret of character development, as with the eternal fascination of lovers, is that there must always be something unfathomable, an element of mystery.

Find Out More...

• Character Tags and Tics, by Victoria Grossack
  
  
• The Secrets of Characterization, by Sigrid Macdonald
  
  
• We All Need Someone To Love: Creating Characters Readers Will Care About, by Victoria Grossack