Whatever universe this island occupies, it has extraordinary properties. Often, you cannot tell when the ocean ends and the heavens begin, nor where the molten lead of the surf transmutes to the solidified lava of the shore, nor identify the point at which the rocky terrain melts into a weary farm building. Land, sea and sky; nature and artifice - these merge together miraculously in Isla de La Palma, a forgotten little sister of the Canaries.
Imagine that a geological cataclysm has bestowed the Isle of Wight with a string of 7,000ft mountains, arranged in the manner of a question-mark through the centre of the island. The remodelled isle is then transported to a point 150 miles west of the Sahara, the furthest-flung of a family of seven. You can't get much more marginal than that. The second-smallest of the Canary Islands hangs to the volcanic skirts of its larger, more popular siblings. La Palma feels cast adrift - which, for the visitor, is a wonderfully liberating feeling.
But first, you need to get there. You know the feeling when a journey has been such an ordeal that you just know you're not going to enjoy the destination? That was how I arrived in La Palma. You can't fly direct from Britain - which, say some, is part of its charm. So I flew from Gatwick to Tenerife's southern airport, and tried to connect with a flight departing from the northern airport.
After a horribly early start, a couple of cancelled buses and a pounds 40 taxi ride, when I finally boarded the (inevitably delayed) plane to the island, I was fully expecting La Palma would feel more like a stress- related illness than a paradise island.
The final approach sorted that out. The pilot came in from the north, providing a splendid flypast of an island that seemed to protrude from the sea like a giant, ragged emerald. A sharp U-turn swung us around for the landing, on a runway that sticks out from the side of La Palma in the manner usually reserved for aircraft carriers. This was clearly no ordinary island.
"Next time, you may want to take a taxi," smiled Gregorio as I climbed out of the car. He handed me a card that showed he was an off-duty cab driver. By day two, the unexpected drain on my finances had left me in no position to take taxis around the island, and I was hitching (embarrassingly successfully) to supplement the sparse bus service around the island.
The buses, though rare, are cheap and reliable: between the capital, Santa Cruz, and the second town, Los Llanos, the cost is pounds 2. The thousands of migratory birds that pause here would cover the journey in eight miles, but by tortuous road the trip takes more than an hour. If you want to make a success of a career selling power steering, set up in La Palma. The airport runway is the only straight stretch of Tarmac on the island.
You soon get the hang of knowing instantly where you are with a single glance. Windswept plains tumbling into the sea means Wagner country, the exposed west coast. More sheltered and gentle terrain, with the grey outlines of Tenerife and La Gomera rising offshore like whales, implies the east coast. And when you can't see beyond the end of your nose, you must be in the mountains.
La Palma's catchline is "The Green Island". In tourist-speak, "green" invariably means "wet". Bearing the brunt of 3,000 miles of Atlantic Ocean makes La Palma the dampest of the Canaries. Even if it's not raining at sea level, you can easily go upwards and check in to a cloud. I spent considerable time trying to reach the various miradores recommended as affording the finest views. But those argumentative clouds always came along for the ride, and I would return to Santa Cruz for the company of humans rather than cumulus.
La Palma has fewer people than the Isle of Wight, with just 80,000 inhabitants - a number exceeded on most days by tourists in neighbouring Tenerife. There are occasional charter flights from Germany, but as a tourist you are a relatively rare species in La Palma. So expect a more than usually generous welcome.
And once you start talking to people, you realise that you're not in Spain at all. For a start, the language has a winningly lazy pronunciation, with none of the Castillian lisp. The suspicion that in fact you're on a misplaced speck of South America is increased when you leaf through the Canary Islands newspaper. Each of the seven islands is covered in turn, all the way down to the toddlers of La Palma and neighbouring Hierro.
The next page is marked "La Octava Isla" - the eighth island - and shows a map of Venezuela.
Since 1492, the Canaries have been part of the New World, spiritually rather than geographically. You can fly direct to Caracas and Havana, the two cities with the largest Canarian communities. And towns like Santa Cruz de La Palma have picked up Latinesque touches, like the exquisitely elaborate galleries ambitiously applied to tall, handsome homes. A main street is named, in the Latin manner, after an obscure Irish adventurer: O'Daly (in Spanish-speaking America, O'Higgins and O'Reilly get namechecks). A replica of the Santa Maria, Columbus's vessel of discovery, is the closest that La Palma gets to a tacky tourist attraction. Walking around Santa Cruz is like rambling through a version of Old Havana where things actually work. There is an energy, an intensity, that you rarely find outside the inner core of Latin American capitals.
The wayward vibrance of La Palma is easier to reach than any of these distant lands. But only just.
The easiest way to reach the island is on a charter flight to Las Palmas, changing to a local flight or ferry. Simon Calder paid pounds 230 for a five- day holiday in Tenerife with Thomson, including charter flights from Gatwick; he travelled on to La Palma on a flight operated by the airline Binter, which has frequent links between the Canary Islands. Fares, though, are high; the one-way ticket cost pounds 40. The inter-island ferries are much cheaper; he sailed back to Tenerife for pounds 10, including a berth. To hire Gregorio Diaz's taxi, dial 44 44 62.
The best books about La Palma are the East and West Walking Guides by David and Ros Brawn. Spanish Tourist Office, 22-23 Manchester Square, London W1M 5AP (0171-486 8077; brochure-line 0891 669920).