Twelve hundred pages arguing that the people who build things owe nothing to anybody, delivered through a railway executive, a strike by the competent, and a sixty page radio speech near the end.
Read in 1980, early enough that I took it more seriously than I would now. That is part of what the book is for. It arrives with total certainty at an age when certainty is appealing.
I got to The Fountainhead two years later and found the same argument in a much tighter package.
What holds up is the readability. What does not is the idea that anyone builds anything alone.