It was raining by the bucket on Cape Cod the other day, so my wife and I decided to take in a movie. We were in South Dennis; the theater was in West Yarmouth, about six miles away. The first three miles were a piece of cake: eight or 10 minutes through uncrowded terrain that could almost pass for the "Old Cape Cod" Patti Page used to sing about. But the last three miles were another story altogether: 40 minutes of bumper-to-bumper agony along Route 28, through a strip-development nightmare that is the Cape Cod of the future.

So it was fitting that at the end of this journey we found ourselves at "Back to the Future," a movie that starkly if perhaps unwittingly depicts the postwar trashing of the American landscape. The charms of this hugely popular film largely eluded me, but I couldn't help being struck by the parallels between the fictitious California town it depicts and the all-too-real Massachusetts resort in which we watched it. In the 30 years spanned by the movie, Hill Valley is transformed from a pretty, peaceful small town into a vast parking lot; this is exactly what has happened to Cape Cod, and it is a terrible thing.

To be sure, it is still possible to catch glimpses of what Cape Cod was like before the Mid-Cape Highway was opened and the peninsula was made available to more people than it can accommodate. The little cluster of bay-side houses in Brewster, where my mother went as a girl and where I was taken as an infant, is still isolated and quiet; the cottage in South Dennis my wife and I have rented the past several summers, though in a heavily built-up area, offers a back-yard view of Follins Pond that borders on the idyllic; the Cape Cod National Seashore has given last-minute reprieve to miles of coastline and sand dunes.

But as you look out to our back yard view, from the near distance comes the steady, unceasing rumble of traffic on the Mid-Cape. This, not Follins Pond or the Cape Cod National Seashore, is the hard reality of Cape Cod in 1985, just as it is the hard reality of Ocean City and Nags Head and Myrtle Beach and Fort Lauderdale -- all the beautiful beaches, most of them little more than spits of sand, that are being destroyed by a society too affluent and careless for its own good. What is happening on Cape Cod is especially startling and alarming, though, because it is happening so fast.

It is happening not merely because people want to spend their vacation at the Cape, but because they want to retire there or they want to live there and commute to jobs in and about Boston. The result is that the pace of construction is breathtaking. The vegetable stands are disappearing; the one we used to shop at is closed now, with an apologetic sign alerting customers to its demise, and no one will be less surprised than I if next summer "Happy Acres" or "Whispering Pines" or some other such development is on the spot. After all, last summer there was a vacant field across Route 134 from Harney's grocery and liquor store; this summer there's a huge supermarket and a huge discount drug store and a string of vacant shops between them, shops that no doubt will be peddling pizza and souvenirs by next summer.

Where most of this growth is taking place -- and Barnstable County, which is to say Cape Cod, is the fastest growing area in New England -- is not along the Cape's two shores but in the wooded area between them. One of the considerable ironies of Cape Cod's development is that although the seashore is presumably its chief attraction, the seashore is available only to the privileged few. To have a view of Cape Cod Bay or Nantucket Sound, you have to have been there forever or be rich enough that price doesn't matter. Otherwise you are consigned to an overpriced cottage -- over $100,000, and the price goes up a few grand every day -- with a view of little except scrub pines and access only to public beaches, which on the Cape are surprisingly few and on weekends resemble not Thoreau's Cape Cod but New York's Jones Beach.

This is taking place against only token resistance from the Cape's townships. Commissions are appointed and studies undertaken -- the hot topic these days is fresh water, of which there is far from enough -- but the developers continue on their merry way. A cartoon in the Cape Cod Times makes the point succinctly. A clam is chatting to itself: "Here's the tranquil quahog contemplating the Cape's rapid growth and development. We residents of this fragile land have an absolute obligation to protect ourselves from unbridled development. Our numbers grow each year . . . New construction cannot be allowed to continue. However, if you're ever in need of a three-year-old half-Cape for under $200,000 . . . "

Cape Cod has become a developer's Klondike, with the entirely predictable result that all of the qualities that make it so lovely and alluring are being wiped out. Yes, you can still sit on Corporation Beach in Dennis on a clear, bright day, looking out to the astonishingly blue waters of the bay and the sailboats quietly coursing them, and say to yourself that you are lucky indeed to be alive. But you are also lucky to have found such a moment's reverie in the bustle and crush of traffic, of construction, of merchandising, of commercialization gone berserk.

It's the automobile that's ruining Cape Cod, of course, just as it's the automobile that ruins Hill Valley in "Back to the Future." The problem is not that it has made the Cape available to the masses . . . unlike Bar Harbor or Newport, Cape Cod has never been a rich folks' preserve . . . but that it makes getting there so quick and easy. The way some of Massachusetts' more egregious loonies drive, you can make it from Boston in about an hour, and without giving the journey any more thought than you would a trip to the neighborhood shopping center. With the distance factor thus effectively eliminated, the Cape has been transformed from a peaceful seaside recreational area into just another suburb of Boston.

Not merely that, but the old Cape is irretrievably gone. The few patches of it that remain are as lovely as one could hope them to be, but the condos and the shopping centers are steadily encroaching on their limited space. One visits them now rather as one visits a museum or a historic mansion or a landmark . . . because they tell us not about the present, but the past. What a great pity this is, and what a loss for all of us.