In 1873, he built the Edgar Thomson works in Braddock, Pennsylvania, to make steel using the Bessemer Process, a new idea. He established many other steel plants, and in 1892, he merged all of his interests into the Carnegie Steel Company. This act from Carnegie is fitting with one of his most famous quotations, "Put all of your eggs in one basket, and then watch that basket" (Andrew Carnegie Film). This firm became one of the greatest industrial enterprises in America. Carnegie later sold it to J.P. Morgan's United States Steel Corporation in 1901 for $400 million, which would be a little over $4 billion today (Andrew Carnegie Birthplace Homepage). .
After retiring, Carnegie's fortune was estimated to be as large as half a billion dollars. From that time on, with the philosophy that the rich have a moral obligation to give away their money, he devoted himself to philanthropy. Although ironic, this man of great fortune strongly believed in the merits of poverty for the development of character and work ethic, and determined that wealthy men should not leave their fortunes to their children, but should give it away, claiming "The man who dies thus rich, dies disgraced." The picture of community service, Carnegie is quoted as saying, "Pittsburgh entered the core of my heart when I was a boy, and cannot be torn out. I can never be one hair's breadth less loyal to her, or less anxious to help her in any way, than I have been since I could help anything. My treasure is still with you, and how best to serve Pittsburgh is the question which occurs to me almost every day of my life" (Andrew Carnegie Film). .
Colonel James Anderson, who Carnegie believes to be his childhood benefactor, established a public library in his hometown of Allegheny City. This library was the first opportunity for Carnegie to take advantage of free information, and he developed a vast interest for knowledge, checking out at least one book a week, and developing himself as a young boy.