Happy 50th Charlie Brown!

Good Grief! Charlie Brown is 50! So are Snoopy, Lucy, and the rest of their gang.

Peanuts, the comic strip featuring the lovable loser in the zigzag shirt, his wacky beagle Snoopy and their unique group of neighborhood pals, marks the start of its 50th year on the funny pages Saturday.

Through more than 18,000 strips over the past half-century, creator Charles M. Schulz has shared the gang's trials and tribulations with the Red Baron and the kite-eating tree and in the pumpkin patch and on the pitcher's mound.

The strip appears in more than 2,600 newspapers in 75 countries. And the Peanuts franchise generates $1 billion in sales each year.

Steve Charla prepares for the Int'l Museum of Cartoon Art's exhibit honoring Peanuts.

Peanuts made an inauspicious debut in just seven newspapers on Oct. 2, 1950.

"Elvis hadn't even come on the scene yet, never mind the Beatles or rap music," said Brian Walker, son of Beetle Bailey creator Mort Walker.

The younger Walker is the guest curator of an exhibit opening today at the International Museum of Cartoon Art which chronicles the first five decades of Peanuts and the work of Schulz, who at age 76 continues to draw single-handedly the 365 Peanuts strips a year at his studio in Santa Rosa, Calif.

The exhibit, which runs through Jan. 30, contains hundreds of collectibles and original sketches that take visitors through the evolution of what has become the most successful comic ever.

There are larger-than-life character props of Charlie Brown on the pitcher's mound, Linus in the pumpkin patch with his security blanket, Lucy dispensing advice for 5 cents and Snoopy, as a World War I ace, flying overhead on his red dog house proclaiming "Curse you, Red Baron!"

Schulz, who donated some of the most recent originals of his strip for the show, is not expected to attend because he prefers not to travel, Walker said. The modest cartoonist declined an interview to talk about his work.

The exhibit offers a chronological view of the development of Peanuts, and shows the remarkable yet subtle development the characters have made over the years -- from their first $1 book to NASA using Snoopy and Charlie Brown's names and images for the space program.

"I'm on the moon! I did it. I'm the first beagle on the moon!" Snoopy proclaimed in a strip than ran at the same time as NASA's mission. "I beat the Russians...I beat everybody. I even beat that stupid cat who lives next door."

The vast majority of the items on display came from the collection of Freddi Margolin, known a"the Snoopy lady." She has at least 20,000 Peanuts items in her Long Island, N.Y., home, Walker said.

The reach of the Peanuts gang stretches far beyond the daily newspapers.

In the 1960s, Hallmark began using Peanuts on greeting cards; now one in every five Hallmark cards has a Peanuts theme. There have been thousands of new products bearing Peanuts characters, television shows, feature films, even a Tony Award-winning Broadway play.

Of all the characters, the personality of Charlie Brown has probably remained the most constant through the years. From as far back as 1952 and possibly earlier, he has worn his trademark zigzag shirt.

He's a born loser who never gives up. And that's his appeal, said Steve Charla, collections coordinator at the museum.

"We all kind of see ourselves in Charlie," he said.

Other Peanuts characters have undergone dramatic changes over the years.

Lucy, for example, started off as a sweet little girl. She soon evolved into a "fuss-budget," Walker said. And Snoopy, strangely enough, used to act like a dog. That was before his flights of fantasy.

The years have taken a slight toll on Schulz, who admits sometimes having to use one hand to steady the other. His lines are a little less firm, but he's given no thought to looking for an assistant. In fact, Schulz says when he dies, Peanuts will die with him.

Until then, though, he's going to enjoy a career that he's never veiwed as work.

"It's just something I always wanted to do," he said in a recent interview with The Palm Beach Post. "I'm not obsessed by traveling. I'm not obsessed by getting everything done in this lifetime. I draw comic strips for the same reason people do water colors or go bowling. I love it."