There are two very good reasons this year – or anytime – for Americans to increase their understanding on an urgent basis of so-called hillbillies, the mostly white people of Scots-Irish stock who are found in the mountainous east-central part of the United States.

The first is that these people are showing advanced symptoms of the problem that is afflicting middle-class Americans at this time – economic inequality. The second is that these people may well vote in numbers this time.

With “Hillbilly Elegy: A Memoir of a Family and Culture in Crisis,” J.D. Vance has written a book that goes some way to helping the rest of us understand what makes these people tick, the lives that they lead that cause them to behave the way they do.

He came from a family from Jackson, Ky., where the men worked in the coal mines until there weren’t any, then moved to Middletown, Ohio, to jobs at Armco Kawasaki Steel, until that went away. Vance got out, serving as a Marine in Iraq and subsequently attending Ohio State University and then Yale Law School before ending up at a Silicon Valley investment firm near San Francisco, a classic “I got out of there.”

Except that he didn’t. The loyalty and secrecy of the hillbilly ethic, including what he calls “the Appalachian honor code,” stayed within him and inspired him, through this book, to try to make it, and its people, comprehensible to the rest of us.

What is so striking about the book is the counterpoint between the utter dreadfulness of Vance’s life, his persistent good humor in the face of it, and his perseverance in doing what he had to do to survive and get out of the Kentucky hollers and the American small town in spite of the monumental barriers.

He watched his drug-addicted mother hauled away by the police in a squad car while the neighbors watched. Part of what he was fighting is summed up in the statement that “working class whites are the most pessimistic group in America.”

The central, horrible, apparent characteristic of hillbilly life, according to Vance, is domestic violence. He is funny about some of it. His grandmother taught him how to fight effectively. He observes that even the best stepparents, of whom he had many, “take some getting used to.”

This book is not “Anne of Green Gables.” Grandmother’s language is eloquently foul. Vance comments that “nice guys never survived their encounters with our family.”

One of the grim facts that he cites is that “the life expectancy of working-class white folks is going down.” Another that I know is true is that “Ohio Januaries are depressing enough as it is.”

There are two problems here, nestling among what seem to me to be the truths about hillbillies. The first is that there are other groups in American society, in different parts of the country, whose situations are just as troubling, if not more so, than the problems of the people Vance writes about. They were outdoors for the most part, not jammed into crowded urban neighborhoods like many African-Americans and Hispanics and undocumented immigrants.

The other problem is that we all know from country songs that there is a definite predisposition for feeling sorry for oneself that is a major characteristic of so-called hillbillies. The story was that if one played a country song backward, one found a job, the car started running again and one’s wife came back.

Vance escapes these flaws through humor and a neat way with words. He calls the miserable experiences he and his sister had with their mother “adverse childhood experiences.” He avoids the perils of what he calls “class tourism,” looking at people he has to please like a sociologist.

“Hillbilly Elegy” is comparable to “Winter’s Bone,” with Jennifer Lawrence’s great portrayal of Ree Dolly in a 2010 movie about a family and a life comparable to Vance’s in terms of enhancing understanding of the lives of hillbillies.

His grandmother told him there was “no greater disloyalty than class betrayal.” Vance has not betrayed his people at all in helping us, his readers, understand them better.