You don’t need a dictionary to tell you that “memoir” is closely related to “memory,” and you don’t need a best-seller list to tell you that memoirs — some of them, at least — are wildly popular. Put that together with the well-worn advice to “write what you know” — what do you know better than your own life, and who knows it better than you? — and hey, why not write a memoir?

Why not indeed?

If you’ve given it a try, you’ve probably discovered that it’s harder than it looks. The challenges inherent in other kinds of writing don’t disappear when you’ve taken your own life as your subject. Structure. Focus. Transitions. Laying down one sentence after another till you get to where you’re going — wherever that is.

You’ll almost certainly discover that some significant incidents in your life didn’t happen when you thought they did, or even where you thought they did. If you consult others who were around at the time — not a bad idea, if they’re still around and if you can do it in reasonable safety both to you and to them — you might find that they didn’t happen the way you remember them either. Others may remember them differently. This doesn’t mean that you’ve got it wrong, only that your version is one of several that may duplicate, complement, or even contradict each other.

Think of what goes down in a courtroom. Witnesses see the same event from different perspectives. They hear the same words spoken but come away with different interpretations, depending on what they know of the speaker and how they remember what was said.

Writing a memoir, you’re not only the eyewitness, you’re the attorney for both prosecution and defense, as well as the judge and jury. It’s not an adversarial process exactly, but be prepared to ask yourself questions that make you uncomfortable.

I didn’t set out to write a memoir, but that seems to be what I’m doing. Memoirs are often written by people who’ve done great things, or taken part in momentous events, or had extraordinary things happen to them. None of these things apply to me.

Well, OK, I have taken part in momentous and otherwise interesting events but usually on the peripheries. And in 1976, the year I turned 25, I started collecting T-shirts from those events. Except that I wasn’t collecting them the way collectors collect things. I was mainly adding to my wardrobe. T-shirts were colorful and cheap. They said something about me that I was pleased to have said.

At some point, maybe when I counted my T-shirts and realized I had over a hundred of them, I said “No more T-shirts.” I said it several times more over the years. When I counted my T-shirts this past winter, I had 190 so you know how that went.

For my 50th birthday party in June 2001 I hung 25 or 30 of my shirts up in the living room. People liked them. They asked questions. I told stories about where I’d got them. That was probably where I first thought that I could do more with my T-shirts than wear them.

But it was almost 20 years before, earlier this year, I launched The T-Shirt Chronicles, a memoir disguised as a blog or maybe a blog disguised as a memoir. I’m 10 posts in and I still haven’t got out of the 1970s. Come check it out and follow if you’re so inclined.