I have a beard, as anyone who’s met me or seen my picture probably knows. I’ve had it a long, long time.

I started out with just a mustache — and when I say “started out,” I mean I have literally never shaved my upper lip (though it was once, and only once, shaved for me), so by the time I graduated from high school I had a mustache.

That was 1972.

I got kicked out of Princeton in February, 1974, and that was when I grew a beard — a Van Dyke.

Then when I dropped out in 1977, I stopped shaving entirely and grew a full beard. I eventually started shaving again when my neck got excessively fuzzy, but I still have a full beard, and except for two brief interruptions I’ve had it since 1977.

I used to have long hair. I started growing it out in 1969. It got cut back somewhat a couple of times, but basically stayed long until 1984, when I cut it for my youngest sister’s wedding, and so Kyrith, who was then a baby, would stop grabbing and pulling it.

I kept it short for a few years, and honestly, I don’t remember exactly when I grew it back out, but it was long (below my shoulders) through most of the 1990s and well into the 21st century. In 2008, though — I think it was 2008, might have been a year or two earlier — I saw a picture of the back of my head and realized I had a bald spot, and that, combined with the long hair, had me looking uncomfortably like Riff Raff from “The Rocky Horror Picture Show.” So that October I cut it short, and it’s been fairly short ever since.

There were other variations along the way, such as color, but we won’t go into that right now — the basics, long hair and full beard, were pretty much as described above.

And here’s the weird thing: People don’t see this.

The first time I encountered this was when I was readmitted to Princeton in the fall of 1975. People who hadn’t seen me since February of ’74 got to see me with my new beard.

Some people didn’t notice. Some saw that there was something different about me, but couldn’t place it exactly. The strangest was the girl who exclaimed, “You cut your hair!”

I pointed out that no, I hadn’t, my hair was still halfway down my back, but I’d grown a beard. She stared and said, “Didn’t you always have a beard?”

I never did convince her that I hadn’t.

Then at my sister’s wedding in 1984, nobody noticed that I had cut my hair, that it was at least eight inches shorter than before. I mean, nobody noticed. No one. When I finally mentioned it to someone, he asked, “Didn’t you cut it back in 1972?”

He’d seen me several times between 1972 and 1984. It was long every time.

I mentioned two interruptions in my beard. One of them was when I sold my beard to Gillette, for research, and there aren’t any odd stories about that, but the other one, well, one morning I just decided to experiment, and shaved half of it off, trimming it back down to the old Van Dyke.

No one noticed. It was like the wedding, except that this time even my own kids didn’t notice anything. So I grew the full beard back, because why bother maintaining the trim if nobody notices?

And I bring this all up now because at Capricon last month, someone I hadn’t seen for a few years saw me and exclaimed, “You grew a beard!”

She had never, ever seen me without a full beard. The actual difference was that I’d cut my hair since she last saw me. Well, that, and I’ve gone mostly gray.

But she saw a difference, and somehow that became I’d grown a beard.

I find this phenomenon baffling.