On the wall of my office hang two pictures. The one picture shows a derelict house - its proportions beautiful, but its windows gaping - surrounded by endless desert. The other is a rather startling shot taken inside the same house showing an empty doorway and behind it a shadowed room filled with a mound of pale sand. The impression of the desert slowly claiming the house as its own is disquieting.

These photographs were taken in the ghost town of Kolmanskop in the southern Namib desert. The place is now deserted but in 1917 Kolmanskop was the wealthiest place on the planet. The desert sands held a vast treasure trove of diamonds and attracted adventurers from all over the world. Those who struck it rich built grandiose houses and lived a privileged but surreal life in one of the most desolate places on earth. It is still possible to visit the general store in Kolmanskop and to take a look at the order book, which is lying open on the shop counter. The orders - caviar, white flannel pants, fine wines - tell of wealth and a fabulous life style. Opera singers were imported from France to grace the boards of the Kolmanskop music hall where the stage still stands. Next door is the hospital where the first X-ray machine in the Southern hemisphere was once installed.

But Kolmanskop's glory was short-lived. When an even richer yield of diamonds was discovered at the mouth of the Orange River, the town emptied. The houses with their tiered balconies and fine pointed brickwork crumbled under the onslaught of a desert wind that never ceases. In 1956 the town was completely deserted.

The photographs have fascinated me for years, stirring my imagination. When I finally managed to visit Kolmanskop in person I knew I would write a book, which would have this place with its terrible beauty as its backdrop. For some time I had been toying with the idea of telling the tale of a man who had killed his brother in a moment of uncontrollable rage. This desolate outpost in the desert would be the ideal hide-out for a fugitive from the law: a man who was also trying to come to terms with his own inner demons. Here, where the ghosts walk even during the day, my hero would start his journey on the road to redemption.

Meanwhile, on the other side of the world, a young photographer named Justine Callaway has taken up the post of caretaker at a beautiful Palladian house in the English countryside. The house is beautiful but it has a tragic history. Nine years earlier two brothers had fought each other in the darkened garden. One brother was killed and the other became a man on the run...

Windwalker is a story about fratricide, redemption and soul mates desperately searching for each other. But it is also a thriller, action novel and ghost story. As I started to write the book, the narrative took me into unexpected terrain. My hero is a cave diver, which necessitated my becoming acquainted with the world of cave diving and the exceptional breed of men and women who practise this truly dangerous sport. My heroine is a photographer and in the course of the novel she captures on film images, which could not possible be real. Ghost photography is a fascinating subject and became a central motif in my book.

As for the characters in Windwalker: Adam and Justine are possibly my most dysfunctional hero and heroine. But even though I found them challenging and often exasperating to work with, they never bored me. May you find their company of interest as well.