I'll start here by writing for those who have not read the book (light spoilers) and finish with those who have (full spoilers).
I'm glad I read this book. The author, born in 1925 (important context), tells an allegorical story of fictional Henry and his perfect life for most of the book. It's a quick little read (probably 2-4 hours). In the last quarter, Roush breaks the 4th wall and addresses the reader, breaking down the story and being very forward with its meaning. As the front flap of the book gives away, this story and purpose at the end is intended for a Christian audience and attempts to rally people for how to live a happier, more purpose-filled life. The book seeks to enrich the perspective of the reader to consider what actually leads to a content life.
(SPOILERS) I sympathize with Roush's purpose with this book - that modernization and globalized society has brought with it great evils, camouflaged as "good things in life." He calls readers to take notice that materialism, and running ourselves busy for its sake, leads to a colorless, feckless life. That's where my shared perspective with the author stops. The story of Henry is painfully oversimplified. "Progress" comes to town (modernization in the form of plumbing and electricity and automobiles) and Henry buys into all of it at once as if he has no choice whatsoever but to go in desperate debt for it -- while also telling us that Henry is perfectly happy without it and doesn't want any of it.
The entire last part of the book, where the author addresses the reader directly, sounds like the ramblings of a stubborn old man who's resistant to change. Keep in mind, the book first published in 1969 and Roush was approaching 50 (around the age that Henry purposefully runs his car off a bridge). He argues that real life is just like Henry's story and backs up his arguments by saying 'who dare deny it' over and over again. Roush, quite literally, likens the mark of the beast to a credit card. He argues that the happy Christian life is like Henry's before progress comes - only concerned with food, water and shelter and a little preparation for a rainy day. Again, I don't disagree with this in basic principle, but Roush creates an entire anti-modern dogma from this. It reads of a cult manifesto. It's not evil to own a car, to have plumbing in your house, to take out a student loan. Jesus did not want us to remain uneducated or to reject modern medicine. Thanks to those who did NOT live as Roush would want - we have things like libraries and life-saving antibiotics for the price of a deli sandwich.
I must also add that the story of Henry, and Roush's glorification of it, strikes me as racist. Looking back to the pre-industrial age in America with reverence is only something a white man can do. Specifically, a white man. I didn't even look up Roush's race, but I have zero doubt he's a white man. Henry is the head of a complementarian, nuclear household, living life by working the farm, and being content with dominoes over candlelight as the respite after a long day. And living on land stolen from Native Americans likely never crossed his mind.
Again, I'm glad I read the book, and I think Roush's point still landed with me and left me with a net-positive in my perspective. But I cannot recommend this book to anyone. Time has not been kind to it.