There is only one way to explain the popularity of otherwise awful television shows like Survivor.

I watched it once, just so I could see what the rumpus was about. As it turns out, once was enough. The contestants, their spats, and the plots--which are pretty heavily padded with theme songs and previews of the not very dramatic decisions that will come "after these messages"--just weren't enough to engage my attention.

But the truth is, a lot of people are hooked on this so-called reality TV. I don't think it's because we're all hopeless voyeurs. The real reason, I think, is a lot less dramatic. These shows satisfy our nosy natures. People are curious about each other and about themselves. By living vicariously through others, we can understand better what we would do in similar situations.

When you see someone on TV eat a rat, you think, "Would I do that if I had to?" The answer, whatever it is, gives you insight you might not have had otherwise. And when you talk about it with your friends you can find out who among you are the rat-eaters, and who would rather starve.

But there are better ways to learn about yourself and your fellow humans than by contemplating the crunch and tang of vermin. One of the best ways is to read other people's journals and to write your own.

Probably the most famous journal, and deservedly so, is Anne Frank: The Diary of a Young Girl. Her parents gave her a diary for her 13th birthday, only weeks before the family went into hiding from the Nazis. It's fascinating to read, not just because it's a reminder of the horrors of the Holocaust but also because of Anne's vivid descriptions of her life hidden in a tiny annex with seven other people for two years.

Another great journal is The Voyage of the Beagle by Charles Darwin. Two things make it excellent: the lush, descriptive writing and the knowledge that this careful record changed the way many of us understand life on Earth.

It doesn't hurt that Darwin occasionally confesses to doing strange things, like trying to ride on the back of a giant tortoise:

I frequently got on their backs, and then giving a few raps on the hinder part of their shells, they would rise up and walk away;--but I found it very difficult to keep my balance.

The oddball son of rich people, Darwin was only 22 years old when he embarked on his five-year trip around the world. At the time, most scholars thought life was the result of a series of creations followed by catastrophes. Most scholars also believed that species didn't change.

Had Darwin not taken all those notes and sketches, he wouldn't have had the credible evidence required to advance his theory of natural selection in the book On the Origin of Species. The book, which sold out the first day it was available, remained controversial for generations, even among scientists. Ultimately, however, the book ranks among the most important contributions to science in history. I don't think any of it could have happened if Darwin hadn't kept a careful journal.

Not all journals change history, though. Some are just great reading. So great, in fact, that history would probably be everyone's favorite subject if only it could be taught exclusively through reading personal diaries. Letters of a Woman Homesteader, by Elinore Pruitt Stewart, paints a picture of what life was like a century ago.

Stewart, a self-described washerwoman, thought she could have a better life if she claimed a homestead in Wyoming. To get a start, she took a job as the housekeeper for a man who was already there, a bagpipe-playing Scotsman (whom she later married). Here's how she describes her early impressions of him:

Mr. Stewart is absolutely no trouble.

As soon as he has had his meals he retires to his room and plays on his bagpipe, only he calls it his "bugpeep."

It is "The Campbells are Coming," without variations, at intervals all day long and from seven until eleven at night. Sometimes I wish they would make haste and get here.

No matter how much you read, though, it won't do the one greatest thing that keeping a journal can do for you: capture your personal thoughts and history, for you and others to devour.

As Anne Frank put it, "When I write, I can shake off all my cares."

Shaken off onto the page, your cares can become a time capsule of who you are and the world you live in. The best journals are great precisely because they create this sense of time and place. There are some old journals that, while historic, are extremely dull. "Mr. Johnson stopped by today. I fed the cows." Boring! This could have happened anytime and anyplace that has both cattle and Johnsons.

What's better is when journals tell stories. Let's say the cow butted Mr. Johnson into a pile of manure. Suddenly, the reading is getting good. It would be even better if Mr. Johnson decided at that moment he was a vegetarian and that he was going to eat tofu from then on. That little detail helps place Mr. Johnson in the late 20th century (if not the 21st).

And it doesn't have to be all words. One of my guilty pleasures is reading a journal that has pictures--something incredibly easy to do today, with digital cameras that let you make prints at home. Audio and video diaries are also very cool. Cyclist Lance Armstrong made one of these (with a little help from the slick producers at Nike).

Sometimes, it helps to write a diary on a particular topic. If you play on a soccer team, you could write a journal about your season. Or, if you've moved to a new city, you can write about getting to know a new place and new people.

No matter how you do it, when you capture the events and people that matter to you, you can understand and remember both of those things better. And so can your grandchildren, who may stumble across them when they're assigned to write a history paper about the quaint and unsophisticated way we lived in the early 21st century, before the invention of personal hovercrafts, dog-translators, and self-cleaning pants.

Or at the very least, they can find out what rat tastes like without actually having to eat one themselves.