This photo array is about Halloween in the subways. Literally. For a few fleeting hours on the night of October 31 New York's subways are overrun with people in Halloween costumes.

The effect is of a waking dreamland. And not just any waking dreamland. On Halloween night, the subways are transformed into some passengers’ fevered dreams of their own subway fears.

For many people fear and the subways are inextricably linked. After all, the anxieties of close urban living take their most tangible form in the subway. There is no other place where one is required to so completely surrender control over one's personal space. We all fear the loss of control. We all sometimes fear the company of strangers. We all sometimes fear being trapped in a confined space. These are fears that go the very core of our being. For many, the subway environment represents a highly efficient way to deliver a powerful dose of these elemental phobias on a daily basis.

Meanwhile, in recent years Halloween has become an enormous social, cultural and commercial phenomenon devoted to the celebration of fear. In New York and other large cities, Halloween night has become a time to celebrate the anxieties of urban living. And what better place to celebrate these anxieties than in the subway?

And so Halloween in the subway seems almost inevitable. It is the convergence of many social and cultural trends -- as applied to a place that for many is the wellspring of phobias far more compelling and immediate than a Stephen King novel.

And yet: How did Halloween in the subway actually come about? The apparent answer is: spontaneously and organically. No one person or organization planned this. Certainly, the Village Halloween Parade contributes greatly to the phenomenon. But it would also appear that many costumed people in the subway are travelling to private parties. In truth, Halloween in the subway has come about because most New Yorkers travel in the subway and on October 31 many New Yorkers happen to be in costume. That is what I mean when I say the phenomenon is "organic."

Because Halloween in the Subway is an organic phenomenon, any attempt to classify it or to limit it will fail. It is not strictly a public performance. It is not strictly a parade. It is not strictly a party on wheels. Or maybe it is all of these things ... but only if you want it to be. The interior of each subway car is a public theater of vivid spectacle ... for those who choose to see it. But many people turn away and turn inward -- as subway riders are disposed to do. It is the subway, after all. In the end Halloween in the Subway remains true to the subway itself.

Step into a subway car on October 31 and you will see superheroes and flesh-eating zombies, princesses both traditional and transgendered, people dressed as insects and as exotic plants, and people who appear as entities known only to them. And you will see people who may or may not be homeless but who are dressed as if they were homeless -- sitting next to homeless people (or is it the other way around?). And you will see many people who are in -- but not of -- the moment.

This is New York. And it is the city at its best -- spontaneous, ephemeral, impossibly heterogeneous yet remarkably tolerant -- and with most everyone taking it more or less in stride.