A surprising answer to the question: What book for a desert island?

You're stranded on a remote desert island, perhaps for years. Forget about Internet access or some wireless device. You're on your own and allowed only one book to accompany you. What book would you choose? One of those classics you've never gotten around to - say, "War and Peace" or "The Decline and Fall of the Roman Empire"?

If you're under 18 or a persistent multitasker, perhaps the prospect of such isolation - Webless - leaves you so anxious that you'd be unable to focus on reading.

But let's pretend.

I know what book I would select: my dictionary, one volume, about 1,500 densely printed pages.

Let me explain. On a recent Sunday morning, I drove over the hills to the coast and strolled on a beach. There's rarely any sun mid-morning on this stretch of Pacific coast, but then there aren't many people yet either. (Crowds on a beach are like cellphone chatterers at the movies - something to avoid.)

I walked where the sand was firm, near the breaking waves. Along the debris line were scraps of crab and eggshells, seaweed, a massive clear jellyfish, pieces of plastic, feathers, halves of blue mussels, and something round, white, almost flat, slightly larger than a quarter. I bent to pick it up. A sand dollar, with the sign of a starfish in its center. A perfect specimen, unbroken. And a rarity.

Over years of occasional beachcombing in my area, along the San Francisco peninsula, I'd found only one other sand dollar. I put it in my pocket and knew what I'd say when I showed it to others: "I found a dollar on the beach." I'm known as someone who picks up pennies from sidewalks.

Later, as I placed the sand dollar next to my other one on a bookcase shelf, I realized that I didn't know what a sand dollar was. I understood the name - it looks like a large silver coin and appears on sandy beaches. But was it a kind of shell, the remains of a living creature? Had any creature lived in such a compact home?

I looked up the name in my dictionary and got one of those links in the great chain of being that amazes me. According to the dictionary, a sand dollar is a type of sea urchin living in shallow water. Sure, I could have done an online search, but this was a low-tech inquiry; the dictionary is never slow to boot up and its pages don't freeze.

Although I know what a sea urchin is, sort of, "urchin" stuck in my mind. Where does that word come from? What was an urchin besides a ragtag wild child?

I'm an editor, so I use my dictionary often. Whether checking spelling, pronunciation, or meaning, I'm in the habit of also looking at a word's origin. It turns out that urchin is derived from a Greek word for hedgehog and Latin for to bristle or tremble.

The dictionary referred me to "more at 'horror.' " Horror? Well, why not? The word "gas" is related to the Greek for chaos. I paged forward to the H words to pursue this connection.

I already knew that hedgehogs are nocturnal mammals with spines - although I tend to imagine them as characters in Beatrix Potter tales - but the dictionary said the word also referred to porcupines. Somehow I was pleased to think of ancient Greece being familiar with hedgehogs. Perhaps they roamed the Acropolis at night.

I recalled a blazing summer day many years ago when I was stuck in Heathrow Airport, giving me occasion to read every line of The Times of London. England had been unusually hot and dry for weeks, and a brief notice in the newspaper advised readers that they might consider putting out shallow bowls of water for hedgehogs' refreshment during the drought. A little interspecies compassion. Absolutely. John Muir said, "When we try to pick out anything by itself, we find it hitched to everything else in the universe."

We know about this connection in a grand abstract way, but here my dictionary was reminding me, not for the first time, of concrete examples of links, deep and old. Porcupine sticks out in English almost as much as urchin, so I looked it up. Perhaps if I'd ever studied Latin, I wouldn't have needed to. It's simply porcus (pig) plus spina (spine). What else would you call it? Not only a living member of the hedgehog family, but clearly a word cousin, too.

But back to "horror." It's from Latin for trembling and akin to gorse and Greek cheros (dry land), leading me far from shallow seawater to territory where hedgehogs dwell. And gorse, of course, is a spiny shrub. All those spiny, spiky things that make you tremble.

If I'd found a piece of coral instead, I'd have discovered anthozoans - flower animals in Greek - particularly a red type produced by a gorgonian, from the Latin for coral, from the Greek Gorgon, or monster - specifically, a snake-haired woman who turns those who look at her into stone. Back to horror.

Now I'll never have trouble remembering what a sand dollar is. And with a dictionary of English, the great borrower language, always with me, I would feel less isolated on the desert island. With such a book - and its references to history and myth - to consult about whatever washed up on shore, I would not be bored on my island.

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