The easiest way to reach the Mer de Glace glacier from Montenvers railway station is to take the gondola ski lift that descends from the platform down to the valley floor, a couple of hundred metres below. Yet Olivier, my guide from the Compaigne des Guides de Chamonix Mont Blanc, isn't having any of that. Instead, he leads me down a path that winds down from the train tracks and is perched far above the glacier that has bewitched tourists for centuries. And then... nothing. Well, save the top of a ladder I'm going to have to clamber down if I want to experience the ice at first hand.
Climbing the rungs down a precipitous rock face for a couple of hundred metres is a strange feeling. You remind yourself it is just a ladder, and you would have to leap off to do yourself any damage. But it is disconcerting, especially when you look between your legs at the valley floor in the distance beneath.
They do this type of controlled risk tourism very, very well in Chamonix, and have been doing so since well before the recent boom in all things extreme. For around 350 years in fact, when a couple of British gadabouts called Wyndham and Pococke were the first tourists to set foot on the Mer de Glace, on their way through the valley on their European Grand Tour. Back then, the ice was at the level of today's train station, but with farming the valley's lifeblood and the villagers terrified of the dragon-like glaciers that loomed over their town, Chamonix's tourism potential was resolutely untapped. Wyndham and Pococke's arrival – and the subsequent publication of a book about their adventures – changed all that, beginning a tourism boom that shows few signs of slowing.
Other winter ski resorts offer summer activities, but few do so with Chamonix's aplomb. This is thanks in part to the fact that the raw materials that make up the wider Mont Blanc range seem to have been put together in a particularly wonderful way. As new sports are invented each year, Chamonix usually turns out to be the best place in the world to go and try them out; it's an adrenalin Valhalla.
Mountaineering? It was pioneered in the valley. Modern Alpinism began when locals Jacques Balmat and Michel Paccard made the first ascent of Mont Blanc in July 1786. Parapenting? Chamonix's thermals have been discovered to be the best in France. Marathon running? The Mont Blanc Marathon is one of Europe's toughest.
In the light of this heritage, climbing down a ladder isn't really worthy of comment, so I tell myself to stop being so ridiculous and try to enjoy the view of the glacier and the Grand Jorasses peak in the distance. Then, with crampons fitted, I follow Olivier and local glaciologist Luc Moreau on to the surface of the glacier and listen as they point out the swiftness with which it is receding. Huge recent rockfalls from the imposing Aiguille du Dru also confirm the constantly changing geological status of the valley. Like all proud Chamoniards, they're friendly and keen to share their knowledge.
Later, over a leisurely lunch back up at the historic Grand Hotel du Montenvers (yes, I did climb back up that ladder), I listen intently as the duo plug some gaps in my Chamonix knowledge. The speed record for climbing Mont Blanc from Chamonix town centre and then descending back down to town? An astonishing four-and-three-quarter hours. And that rumour about how one winter in the Sixties, it simply didn't snow? Completely true, according to Olivier.
Years ago, I spent a couple of winters in the valley, drawn by its reputation as one of the world's greatest ski resorts, but this is my first summer visit to the town. Already I'm impressed. As well as glacier walking, I'm due to attempt rafting, mountain biking and walking during a busy three-day itinerary.
I'm staying in the Hotel Labrador, which overlooks the golf course – and also has clear views of Mont Blanc, Western Europe's highest peak. Later that first evening, I head into the centre of town to try one of the valley's Michelin-starred restaurants. (Back during my season days, the closest I got to eating out was working as a restaurant "dish pig" as I tried to eke out a living as a lowly "seasonaire".)
Le Bistro, a new restaurant with a Michelin star, is my first stop on a happy tour of Chamonix's new culinary frontline. I tuck into the taster menu with gusto: five small main courses – aubergine caviar, beef tartare served like a sushi carpaccio, deep-fried courgette flowers and a rare rack of lamb – followed by a cheese board and dessert for €65. I'm feeling nicely sated by the time I get back to the Labrador.
Further re-evaluation awaits during the next morning's mountain biking at Le Tour. Of the five ski areas that make up the resort of Chamonix, Le Tour sits at the head of the valley, about 20km from Chamonix town centre. It straddles the border with Switzerland and is one of my favourite winter ski areas, so I'm excited about mountain biking the same terrain.
I meet my guide at the border hamlet of Vallorcine and "upload" on the gondola lift to a height of around 2,000 metres. Mathieu is another exemplary guide, a local mountain hand with great English who looks as though he was born with a harness around his waist.
Soon, he is gently guiding me down winding pistes and trails that lead back down to the village of Le Tour itself. For a mountain bike novice such as myself, it is tough work, and I'm soon wheezing and being left behind by experts whizzing past in full body armour. But by the time I reach the valley floor I'm beginning to get to grips with it, although I do almost fly over the bars on a couple of the steeper descents.
Later that afternoon, I begin a final adventurous excursion of the trip: rafting down the river L'Arve. During the summer, L'Arve is fed by silty meltwater from the glaciers which turns the usually mellow river into a more treacherous waterway. And it is cold, too: 4C, which means I'm all togged up in thick neoprene to protect me should I fall in.
Within 30 seconds it becomes clear that my all-in-one garment isn't just for show. My guide Ben Berlioz appears to be making it his mission to pitch me bottom-first into the freezing water.
Ben is a testament to the valley's inexorable pull. "I came here when I was 20 to do a ski season and I never left. I knew I'd end up staying here as long as I could." Ten years later, Ben skis during the winter and is a river guide during the summer.
Later that evening, freshly showered and pink-cheeked from the day's exertions, I enjoy a final blow-out at the Hotel Eden in Les Praz, just on the outskirts of Chamonix. With an expatriate English owner, elegant French waiter, exquisite views of Mont Blanc, walls covered with images of local daredevils skiing and climbing among the peaks, the Eden sums up modern Chamonix perfectly. The cuisine is simple, a straightforward blend of French standards and modern mainstays, as typified by my scallops with salmon and grapefruit to start and Cajun chicken with confit of sweet potatoes and coriander crème fraiche for the main course.
I'm so tired that I can barely finish my post-prandial brandy. But later, as I fall into bed and enjoy one final moonlit view of the mountains, I promise myself that this won't be my last summer trip to this most celebrated of French ski resorts.
The writer travelled with easyJet (0905 821 0905; easyjet.com), which flies to Geneva from a wide range of UK airports. Flights are also available on Swiss (0845 601 0956; swiss.com/uk), BA (0844 493 0787; ba.com), Bmibaby (09111 545 454; bmibaby.com) and Flybe (0871 700 2000; flybe.com). Geneva can be reached by Eurostar (08705 186 186; eurostar.com) from London St Pancras via Paris.
Transfers from Geneva were arranged by Mountain Drop-offs transfer services (00 33 4 50 47 17 73; mountaindropoffs.com).
Le Labrador Hotel (00 33 4 50 55 90 09; hotel-labrador.com).
Le Bistrot (00 33 4 50 53 57 64; lebistrotchamonix.com).
Grand Hotel du Montenvers (0 33 4 50 53 99 16; compagniedumontblanc.fr). Maison Carrier (00 33 4 50 53 05 09 ; hameaualbert.fr).
Hotel Eden (00 33 4 50 53 18 43; hoteleden-chamonix.com).
A one-day Multipass Aiguille du Midi and Montenvers costs €€48.50 (00 33 4 50 53 22 72; compagniedumontblanc.fr).
Glacier walk and mountaineering with Compagnie des Guides Ice School costs €93 (00 33 4 50 53 00 88; chamonix-guides.com).
Mountain biking and rafting with Cham Aventure costs €37 for rafting and €70 for biking with a private instructor (00 33 4 50 53 55 70; cham-aventure.com).
Chamonix Tourist Office: 00 33 4 50 53 00 24; chamonix.com