The Garland High Class of '65 was a big one, the last crop of seniors to leave before graduates were split with the new South Garland campus. Theirs was a top-heavy graduating class of 751 seniors.

 

Since then, they have had 40 years to scatter. They have moved and married, died or divorced, changed their jobs and even changed their names. Some stayed close to home. Others left and returned. Some left and stayed gone.

 

It's the natural diaspora of any group of young people stepping across the threshold of adulthood. Four decades after the fact, how many of them could you expect to track down again? Two hundred, maybe? Fifty?

 

Steve Rhodes, with a single-minded dedication that bordered on obsession, set out to personally invite every single one of his classmates to their 40th reunion.

 

He started in July. Last week, he found the last of the "lost ones," a pediatric hospital nurse in the East Texas town of Mount Pleasant.

 

"I said, 'I'm just going to call 'em all," ' said Mr. Rhodes, a retired software designer living in Campbell, Calif., near San Jose. "My goal was to find everybody."

 

This was no simple task. Even professional alumni-tracking services typically report finding an average of 40 percent of any graduating class. Time and distance reduce the odds.

 

But Mr. Rhodes, a self-described "math nerd" with a doctorate in computer science, figured he could find a way. He assembled a team of volunteer alumni to work as detectives, and they went to work.

 

They didn't have much to start with – just the names and addresses of 66 people. From those 66, the volunteers asked for leads on finding others.

 

By mid-July, Mr. Rhodes said, they still had 549 people to locate. By the start of September, they had the "lost list" down to 175.

 

"You find the easy ones first," he said. "It was a really complex, hard problem."

 

But Mr. Rhodes, clearly not a man to shirk from a challenge, persevered. His goal, he said, wasn't to badger anybody to come to the reunion, which will be held this summer.

 

"They could choose not to come – that was OK," he said. "I just wanted to find everybody."

 

Mr. Rhodes estimated that he talked to thousands of people on the phone: parents, siblings, neighbors, co-workers and wrong-guess dead-ends. He traced a man named Billy Bryan to Oklahoma, only to find it was the wrong one.

 

"But I thought to ask him if he had ever run across another Billy Bryan," Mr. Rhodes said. "He said, 'You know, I did once' " – and that was the lead he needed.

 

In another case, he despaired of ever finding Phillip Evans. He finally decided to call every Phillip Evans listed in the United States – and eventually found the right one in Blue Springs, Mo.

 

Some hunches were wrong: "One woman had no address but a P.O. box in Arkansas, and I was sure it was the right one," Mr. Rhodes said. "When we were in school, she lived out in the country and had a P.O. box. ... I figured she still liked living in the country."

 

Good guess, but three letters later, he found out it was the wrong woman.

 

In another case, three sources reported one classmate as dead – until Mr. Rhodes made a call that the allegedly dead guy answered.

 

Throughout the fall, Mr. Rhodes would stay up late every night, preparing lists of leads and phone numbers for the following day's calls. If he had only an address, he would call neighbors and ask them to knock on the prospect's door and ask whether he or she were a member of the Garland High Class of 1965.

 

Incredibly, he got complete strangers in faraway cities to help him out, knocking on doors or checking names on mailboxes. A few people hung up on him. Mr. Rhodes would patiently call them back and ask again.

 

The by-product of his efforts is a fascinating snapshot of the social habits and migratory patterns of 20th-century Americans. Mr. Rhodes kept careful statistics, sometimes comparing them with census figures to determine how close the Class of '65 came to the U.S. norm.

 

He found, for instance, that 82 class members have died (a slightly below-average percentage, given an average age of 58). He kept records of marriages and divorces between class members and tallied the numbers who had left Garland or left Texas.

 

Only two were living out of the country: One is a missionary in South Africa, the other a teacher in Britain.

 

Of those who left the state, the largest number relocated to California. Colorado was No. 2.

 

I asked what kind of turnout is expected for the reunion.

 

A lot, he said – maybe 300 to 500 people.

 

"It's more than a reunion this time," Mr. Rhodes said. "It's a kind of re-bonding."

 

His reasoning runs like this: Ten years after graduation, only the most successful alumni show up, to preen before their old classmates.

 

"But when you get to 30 or 40 years, they're just happy you're alive," he said. (Another statistic: 49 years from now, there will be only one surviving member of the Class of '65).

 

I asked Mr. Rhodes whether he's one of those "glory days" types who yearn for their lost high school days, and he laughed.

 

"I was on the football team, but out of 40 players, I was the worst one," he said. "I wasn't the leader of the class, or anything like that.

 

"I enjoyed high school. And I've enjoyed life ever since."