Going into last month's Comic-Con (free trial required), I was convinced that comic books were a huge business worthy of our attention as investors. I've since learned four things that further my interest in stocks that owe some of their success to comics:

1. Comics are mythology, and mythology is big business
When entertainment executives talk of mythology, they're referring to timeless stories. In comics, they're referring to characters so long established that they've become widely beloved. Think of Superman and Batman.

At Comic-Con, studios were looking for new mythologies as they profit from the old ones. Of all the studios, I'm most interested in Time Warner (NYSE: TWX). The DC Entertainment division is charged with bringing Time Warner's library of DC Comics characters to life in new ways.

"One of my jobs is to try and get all of our characters outside the comic books to everywhere else," says DC Entertainment's chief creative officer, Geoff Johns. "We all love [these characters]. We want the rest of the world to love [them], too."

The strategy appears to be working. This November, Sony's (NYSE: SNE) Online Entertainment Group will release an online multiplayer game based on Time Warner's DC Comics characters, including the Man of Steel and the Dark Knight. I've played the game, and I think Time Warner and Sony have found a winner.

2. Comics are also brands, and good brands produce high margins
For Johns and others, licensing deals are the products of not just history but also careful brand management, the sort that sets apart consumer names such as Coca-Cola and Nike from rivals. But don't take my word for it. Listen to what Johns says when answering a fan's question about movie plans for Wonder Woman.

"Wonder Woman is a very important character to the world and to us at DC and [DC Entertainment]. I wouldn't be surprised if you saw a lot more of Wonder Woman in the years ahead," he said. Translation: While we can't say anything yet, we'll be deliberate in maximizing the lifetime value of our intellectual property.

Legendary comic book creator Stan Lee was more direct when talking about Starborn, a new costumed character imagined by Boom! Studios, a publishing partner with Lee's Pow! Entertainment. "It's so intellectually complex, it makes Star Wars look like a quickie," Lee says of Starborn's origin and storyline.

The comparison to one of the greatest movie franchises of all time could have been spur-of-the-moment, but I don't think so. At 87, Lee is still fast on his feet. He was at Comic-Con to do business, and he does better if Boom! characters such as Starborn go on to appear in books, in movies, as action figures, and on cereal boxes.

3. Comics trace back much further than any of us think
For me, serendipity is always the most enjoyable part of an event like Comic-Con, and last month's excursion offers no exceptions. I met comic book retailer Robert Beerbohm riding the elevator early on the first morning of the show.

Beerbohm was as engaging as he was opinionated, which isn't surprising. His colorful comics-selling history spans from 1970s San Francisco, where he says Robin Williams and the Grateful Dead's Jerry Garcia regularly bought from his stores, to Warren Buffett's Nebraska today.

His tales thrilled me as a comics fan. But the investor in me was equally enthralled. Beerbohm has a view of the industry that dates back more than four decades. He has attended every Comic-Con since the first one in 1970.

In the years since, he's been on a quest to discover the origins of the comic book industry. He's found that Americans were producing and buying comic books as far back as the mid-1800s. I was privileged to get an up-close look at the yellowed gems he'd found.

You'd think Beerbohm's sense of history would reveal a bias toward some bygone era of comic-book storytelling. Instead, he asserts that while their wrappings may have changed -- we'll be reading nothing but digital comics in a few years, Beerbohm predicts -- the stories that readers and movie studios crave haven't changed much at all.

4. Toy brands are learning from the comic book kings
For as much as Hollywood's influence could be felt at Comic-Con, it paled next to the influence of gamers and toy makers. The big game and toy brands increasingly see their games as Disney (NYSE: DIS) sees its characters: brands to be managed.

Hasbro (NYSE: HAS) is making a massive effort in this area. Chief Marketing Officer John Frascotti says that licensing of the toy maker's various brands, such as G.I. Joe and Transformers, is the "critical, key piece" to unlocking brand value. History says he's right.

Through its first two films, the Transformers franchise has produced more than $1 billion in merchandising, Frascotti says. A third film is planned for next July. Future projects involve movies based on pliable kids toy Stretch Armstrong and two of the company's most popular board games, Battleship and Risk.

Mattel (NYSE: MAT), whose booth was near that of its toymaking rival, could follow Hasbro's plan, which was born of Marvel's strategy -- the same strategy that got Marvel a $4 billion buyout offer from Disney. See the pattern? This, Fools, is the comic book business. And it's making some people very rich.

Disney and Coca-Cola are Motley Fool Inside Value pick. Coca-Cola is also a Motley Fool Income Investor recommendation. Disney and Hasbro are Motley Fool Stock Advisor selections. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings. The Motley Fool owns shares of Coca-Cola. The Fool is also on Twitter as @TheMotleyFool. The Fool's disclosure policy has never actually pledged the Green Lantern oath. But it couldn't hurt, right?