Basically, the mindset and approach that Andrew Carnegie, who knew nothing about the steel industry, used to become the greatest steel industry mogul ever, with no background in steel. It laid out a road map of how the "every man" can organize himself to the same approach for his own goals, to become more efficient and cut out wasted effort in his process, to achieve his own unique goals, without reliance on government, which at the time (in the midst of the Great Depression) was not what the government wanted.
This is why the book was "controversial" and got heavily edited due to pressure from above (gov't), because it focused on freeing the individual, not making him conform to a system of dependency.
However, if you think simply reading my "summary" will give you all the insight you need in my brief "cliff note," it won't. I'm not that good. To get the benefit, you actually will need to do the work, locate a copy of the original and read, as the details of cause and effect are in the book, not my humble summary. Benefit requires effort, either you'll do the work to receive it or you won't.
Happy trading!