This is an early post-apocalyptic novel. The author George R. Stewart was not a science fiction author, but you would not know it from the way the novel is written. It fits very much into the science fiction novels of its period.
The book's prose is the biggest problem. His writing can come off as a bit like a sermon at times, and while readable, does not entrance.
The structure of the book is interesting. It is divided into three parts. These parts focus on three different time periods in one characters life. That character tries to and fails to preserve the civilization that he has lost. What's most interesting is that to some degree this attempt to preserve the lost civilization is seen as misguided. In the end a new civilization starts to assert itself. The book strongly identifies with the main character, so the fact that he is in some ways wrong about what needs to happen is one of the books key strengths.
Another strength is the italicized passages which portray the general changes to the Earth after human civilization falls. While many of the details are likely wrong, the general picture, which is of the Earth adapting and carrying on as a new equilibrium is reached is compelling and also very unusual in the post apocalyptic genre.
The book has a lot to recommend, and I rate quite harshly, so that three stars is quite harsh for the book, but the prose and also the characterization are disappointing.