Steve Manning discovered Canyonlands the way most people do: Rambling down a rutted dirt road just to see where it would go.

"My Volkswagen thought it was a Jeep," said Manning of his first Canyonlands trip in 1967.But that first trip sparked more than just a love of unspoiled vistas and deep red canyons. It kindled what has since become an obsessive passion for Utah's smorgasbord of prehistoric rock art - some of it many thousands of years old.

"I saw a lot of stuff right alongside the road," Manning said, "and I wondered what it all meant."

He couldn't shake that sense of wonder and mystery. He went to the library and checked out everything he could on the subject, but found little to satisfy his curiosity. He checked with local scientists, but they couldn't tell him much, either.

If the scientists didn't know much about rock art, maybe the people of rural Utah did. He began talking to people in southern Utah, who directed him to new and better sites.

"The more stuff I found, the more interested I became," he said. "The more people I talked to, the more I learned about rock art. There reached a point where I found I knew more about rock art than the park rangers."

In fact, rangers at Canyonlands National Park have used Manning on more than one occasion to explain or guide them to rock art sites.

In the past 20 years, Manning has parlayed his interest in Utah rock art into an widely respected expertise. Though not an archaeologist or anthropologist, has become the state's authoritative resource on rock art.

Manning is one of Utah's growing number of amateur archaeologists, and is winning praise from professionals for his research. For several years Manning has been engaged in an ambitious project even he admits will probably require more years than he has left to live:

He is cataloging all rock art sites in Utah.

"I'm wondering why, myself," he laughed. "Maybe it's because I love a good mystery, and this is good mystery. We have all these clues and no answers as to what it all means. It's as if someone sent you a 5,000-piece puzzle in a brown paper bag with no clues as to what it is."

By cataloging the many varieties of rock art sites throughout the state, Manning believes he can piece together much of the mysterious puzzle etched on canyon walls.

There are 4,000 to 5,000 rock art sites in Utah, said Manning, a research chemist at the University of Utah. A site can be a single drawing, or it can be a panel consisting of several hundred individual drawings or it can include several panels in one general location.

"To catalog the whole state is definitely a long-term project," he said. "Maybe I'm crazy, but I'm having a great time trying."

Manning's wife and seven children, though not sharing the obsession, have learned to adapt to Manning's peculiar hobby. Spending weekends and holidays in the desert has become a way of life for the entire Manning family.

"I'm lucky my wife likes camping," he said.

There is more to Manning's research than just personal satisfaction.

"I'm doing it because it's fun, but also for the scientific study," he said. "There are a lot of unanswered questions about rock art, and I'd like to clear up some of the problems and inaccuracies about rock art."

Rock art research for the first time is enjoying popularity among professional researchers, thanks to the work and encouragement of amateur archaeologists like Manning.

"I have always maintained that archaeologists are digging in ancient garbage dumps, and the people who study rock art are looking in ancient libraries," Manning said. "You can learn things from rock art you can't learn from digging in the ground. Now the experts are beginning to see that."