IF YOU CAME THIS WAY: A Journey Through the Lives of the Underclass, by Peter Davis, John Wiley & Sons Inc., New York, 202 pages, $22.95.

“If You Came This Way: A Journey Through the Lives of the Underclass,” by Peter Davis, is a travelogue of sorts. After being mugged outside of his upscale apartment in New York City, Davis decided to study the class of people who might be compelled to stuff a gun in his face and take his wallet. So he went on a gentleman’s journey through the underclass of Chicago, Los Angeles, Oakland, San Antonio — and Bangor.

Even though the poor are always with us no matter what the town or time, it’s not very often that the Queen City finds itself in the company of these other urban American centers. Bangor is in this book because Davis now lives in Castine.

The bulk of his writing career, however, has been spent elsewhere — growing up in California, traveling as a reporter and living in New York City.

In “If You Came This Way,” Davis turns his researcher’s eye to the lives of the American underclass, also called the persistently poor, who number between 800,000 and 75 million depending on how hard-core the definition of “poor” is.

He walks down their streets in the South Side of Chicago, talks with hookers on a street corner in Los Angeles, and eats in the Salvation Army soup kitchen in Bangor. At one point, he dresses as if he were poor and hangs out for a while with the real thing.

He goes on what he calls “the adventure of my life” to understand how the underclass lives, to record his findings, to alert others of his middle-class kind about the hidden truth of American poverty — that it exists in every corner of the country.

Davis’ prose is eloquent, sometimes funny, and almost always self-effacing. Just when the reader is about to get flustered with what appears to be cavalier assertions on Davis’ part, the author admits his own shortcomings, blindness and powerlessness.

He can’t help it that he had a swimming pool when he was a child, or that he can afford to take his family to the Grand Canyon on vacation. All that might appear to undermine his work, but there’s an unusual sincerity about Davis. Some might call it the credulity of privilege, but Davis reveals himself as a good man; helpless in the face of American poverty, but well-intending.

As any solid reporter would, Davis wants to walk a mile in the shoes of his topic. His book-length article never steps out of the realm of reporting, even when Davis includes pensive personal digressions.

But Davis also has the skill and sensibilities of a storyteller. There are times, in fact, when “If You Came This Way” reads like fiction. There are stories which are so wrenching that the reader wishes they were fiction. There are, of course, plenty of first-person tales of life on the crack-infested, gun-riddled streets (such as the one called “Makes Me Wanna Holler” by Nathan McCall), which have an effectiveness that Davis can’t imitate. But his personal queries are no less cogent.

His work is what you might expect from someone who has written two previous books, “Hometown” and “Where Is Nicaragua?” as well as the landmark Academy Award-winning documentary “Hearts and Minds,” about the senselessness of the American involvement in Vietnam. He also wrote Emmy Award-winning “Jack,” a biography of John F. Kennedy.

Although there are no uplifting moments in Davis’ account of homeless, hopeless case studies in “If You Came This Way,” there is one story that will grab the local interest in a second.

Davis befriends Kelso Dana Jr., a 19-year-old Aroostook County boy who, nine years earlier, was forced to eat maggots and frogs when his father threw him into a well and left him there for nine days.

There are other horrible stories about snowbabies, the infants born to mothers addicted to cocaine, and sprayheads, children who inhale common household products.

But Dana’s story is the one that hits closest to home in more than one way. Dana and the teens who hang out at the Paul Bunyan statue are, after all, our neighbors.

Davis has no real solutions but views the increased awareness he got during the researching and writing of this book as an immensely educational opportunity.

And the tone, which some may occasionally find speckled with noblesse oblige, may be a good first step for those readers who are used to sweeping the poor under the Oriental rug.