In 1982, I returned from the Andes to find Raiders of the Lost Ark playing in British cinemas. The opening sequence, in which Harrison Ford rolled down a series of booby-trapped tunnels in order to seize a solid gold idol was a tour-de-force. It managed in just ten minutes to pack in every conceivable myth about South American exploration: the silhouetted Indians padding through the shafts of light thrown by the jungle canopy; the lone explorer, let down by treacherous assistants but determined to find the temple come what may; the battered map almost disintegrating in the sunlight. Best (and perversely most true to life) was the moment when Indiana Jones loses the idol to his arch rival, René Belloq, the suave but of course treacherous French archaeologist, simply because he hasn’t taken the time to learn the local language: ‘If only you had learnt Hovitos,’ sneers Belloq (who has), as Jones flees the on-coming Indians with their arrows and poisonous blow-pipes.

Seen at full volume in a West End cinema when I was fresh from Peru and, it was terrific, even if far removed from the less glamorous reality I had been experiencing. ‘Raiders’ was a replay of many a matinee movie cliché, like the old deodorant ad in which the hero or heroine, sprayed with a symbolic ‘v’ on their back, hacks up to the top of an ancient temple and still emerges with the sprayed area immaculate.

Since then, the computer game Tomb Raiders has provided endless cybernetic variants of the same story. Players can live out Indiana Jones type adventures of discovery as they advance into pseudo-Incaic labyrinths. What’s more, their leader Lara Croft has the considerable advantage of being more nubile and less bossy than your average sweaty, real-life explorer.

As a powerful mythopoeic base on which to build fantasies of confrontation with an alien culture, the Inca world has few rivals. But just as the lure of the Inca myth has increased, so any actual understanding of the Incas themselves has become obscured, let alone of the true nature of exploration in the Andes.

The White Rock is an attempt to present a clear-sighted view of that Inca culture, drawing on my journeys throughout the Inca heartland near Cuzco and across the vast empire they created. Along the way I travelled to some of the most remote Inca sites and talked to leading archaeologists and explorers working in the area.

As I did so, I became more and more aware of the discrepancy between popular preconceptions about the Inca and the actual evidence on the ground. Deciphering that evidence is complicated by the fact that the Incas left no written history and almost all that we know about them comes from the often biased accounts of Spanish conquistadors and from the suppositions of archaeologists. Inca studies, compared to Egyptology or our knowledge of the Classical World, are still in their infancy.

The very familiarity of Machu Picchu causes problems and can lead us to forget how little we still know about the people who built the place. Few visitors to Peru travel beyond it.