He was the fifth grade teacher to have at my elementary school. Everyone wanted to be in his class; getting assigned to the other fifth grade teacher meant missing out. Missing out on all the cool stuff he had around the classroom, missing out on all the fun things he taught, missing out on the warmth of his regard.

But most of all, missing out on The Rule.

Be appropriate

He wrote it up on the first day, in big letters, in the top right corner of the blackboard. Then he turned to face the class and folded his arms. His expression was a challenge to us all.

"This is the only rule in this classroom. Be appropriate. You're fifth graders now. Next year you're going on to middle school. I figure you know what's appropriate behavior in a classroom. So I won't write up a whole long list of do's and don'ts. Do remember, however, that I am the final judge of the appropriateness of anything you do or say.

"This isn't a soft option. I will give you detention if you act inappropriately. You will still get citizenship grades." Then he smiled, and it was like the sun coming out. "Do it right, and we can have a great time this year."

Be appropriate

The Rule meant we couldn't weasel our way through loopholes. We had to think about our actions, and the consequences of our actions. Behaviour was about judgment, not about ticking off our deeds and misdeeds against a list of rules.

It was heady stuff for a bunch of ten year olds. We spent the first weeks of the year in a kind of moral vertigo, trying to find our feet.

Like all kids, we explored the boundaries of appropriateness. And he would pull us up short, like any teacher. "That was inappropriate," he would say, assigning detention after an incident of bullying, or a classroom disruption. But the real punishment was the loss of his esteem, the feeling that we'd failed his trust in us.

Be appropriate

The Rule wasn't the only unusual thing in his class. He was the kind of teacher who had a loft in his room, and allowed the appropriate number of students (two) to sit in it during lessons. He taught us the Pythagorean Theorem, and how to make a rhombicosidodecahedron out of construction paper.

He was famous for his class pets. The doves were long gone when I studied with him, and the iguanas just a memory (though the tale of Iggy 2, who escaped, and was only found when a neighborhood woman phoned the police to complain about the dragon in her garage - that story lived on). We had Jojo and Igor, a pair of California king snakes. It was not appropriate to take them out of the classroom (particularly not into the school office, wrapped around your neck, David...). It was appropriate to gather in a circle and watch them eat a mouse, or to hold them when you didn't have to be working.

But the story that spread his name throughout the school district, more than the Rule or the pets, was the bottle caps. He'd decided, a few years before, that he wanted to show his class what a million of something - anything - looked like. It had to be something small, cheap, and ubiquitous; he picked bottle caps. So we, like several years of his students before us, would pick them up off the ground, save them from family picnics, and scrounge them from the local ice cream parlour. Every morning, we'd bring them in, count up, and add the day's haul to the total posted on the wall. The caps themselves were stored in big clear plastic bags, so that my year, for instance, could see what two hundred thousand bottle caps looked like.

Be appropriate

So there it was, writ large enough for even ten year olds to read. Take responsibility for your own actions, like the grownups do, and you get to do all kinds of neat stuff.

His life hammered the lesson home. He was clearly a grownup, doing all the grownup things like having a job, paying the rent, dealing with other adults. Responsibility. But he drove an orange convertible MG, probably the coolest car any of us had ever seen. He did karate (he got his black belt my year). And he seemed to have so much fun.

Being a grownup didn't seem so intimidating, when you looked at it like that. You could get all the toys you wanted, have all the fun, and maybe even be as wonderful a person as he was, by just following the Rule.

Be appropriate

I was fifteen when it all came apart. The news spread like wildfire through our tiny town. His former students gathered in groups on the high school campus to discuss it.

He'd been stupid. Maybe he wanted to get caught. It wasn't the nunchuks the police found in his house when they searched it, nor the rattlesnakes, that broke our hearts. It was the thing that caused them to get the search warrant in the first place. The pictures of the 12 year old girl from his neighborhood, which he'd gotten developed at a local photo store. They were...not appropriate. The developer took one look and called the cops.

I suppose we should have been devastated. His downfall should have destroyed the legacy of his lessons and demolished the value we placed on the Rule. But it didn't happen that way.

We, collectively, squared our shoulders and went on. The day we heard the story was the day we took the final step that any student can take. We had surpassed our teacher in the subject he taught.

To this day, I think you can pick one of his students out of any crowd. We learned it early, we learned it the hard way, and we learned it well:

Be appropriate