The big question
Why are we asking this now?
Because the climber nicknamed "Spiderman" has just scaled the 88- storey, 452-metre (1,483ft) Petronas Towers in Kuala Lumpur, the third tallest building in the world. Robert, who ended up in police handcuffs, almost disappeared into the smog above the Malaysian capital on Tuesday in the latest of the escapades that have made the 47-year-old Frenchman the greatest daredevil of modern times.
What's his 'previous'?
In a 14-year career as an "urban solo freestyle" climber, Robert has scaled most of the world's highest landmarks, including the Eiffel Tower, One Canada Square in Canary Wharf and the Empire State Building. This week's climb was Robert's third attempt at conquering the Petronas towers, having been thwarted by security guards in 1997 and 2007. His skyscraper count will soon hit 100.
Why buildings rather than mountains?
Robert was a gifted rock climber, honing his skills as a young boy on the rocks around his home in the south of France. Soon abandoning the safety devices employed by most climbers, he found freedom - and an addictive frisson - in solo ascents without rope. In 1993, he completed a record-breaking climb in France's Verdon Gorge. When he was invited to Chicago a year later to shoot a climbing film with a twist, he never looked back. "The city of Chicago had just opened a door to a whole new universe," he wrote in his autobiography, With Bare Hands, "a range of mountains of steel and glass".
How hard is this kind of climbing?
Hard enough to require the strength to perform pull-ups with a single finger (Robert can do three in a row). Wearing climbing shoes and with chalk on his hands for a better grip, Robert seeks out hand- holds in window ledges and other protrusions, lifting his wiry frame with feline fluidity. Some buildings are easier than others - Robert barely broke into a sweat when he climbed the Lloyd's of London building during April's G20 protests. "It's easy and not that tall," he said the day after the climb. But smoother, taller buildings are tougher. "Skyscrapers look repetitive but that puts huge strain on the body, says the British free climber, Leo Houlding. "The smooth surfaces can be dirty and slippery especially in polluted cities."
How dangerous is it?
Very. It's a testament to his skill that Robert has fallen only once in an urban setting. Fortunately the slip came as he perched on traffic lights for a photo shoot. He needed 40 stitches then but had far more serious accidents in his rock climbing days. In 1982, he fell 15 metres on to rock, breaking both arms, his pelvis, and nose. He fell into a coma for five days and was told he would never climb again. He did, of course, and has since come closest to death during an attempt on La Grande Arche de la Defense on the western outskirts of Paris. Heat exhaustion near the top left him dizzy and he had to be rescued from the building's mirror-like walls.
Is what he does legal?
Not usually, and that's part of the appeal for Robert. "We are living in a world where everything is based on security," he says. "Sometimes doing the forbidden can be nice." He could face a six- month sentence for his latest climb and has been banned from, and arrested in, more cities than he can remember. His image as a celebrity outlaw has even been known to seduce the authorities. When he climbed the Lisbon Bridge, police let him off with a 100 fine after a few games of poker.
Is there anyone else like him?
Nobody in the tiny urban solo freestyle community challenges Robert. He is most frequently compared to another French daredevil fascinated by twin towers. Philippe Petit - whose audacious tightrope walk between the twin towers of New York's World Trade Centre was the …