Adam Smith did not mean what most people think he meant
The 'invisible hand' appears exactly once in the Wealth of Nations. Smith was deeply suspicious of corporations, skeptical of merchants, and anti-monopoly in ways both modern sides find inconvenient.
Adam Smith published 'An Inquiry into the Nature and Causes of the Wealth of Nations' in March 1776. It is one of the founding documents of modern economics. It is also one of the most misread books in the Western canon. It arrived sixty years after John Law had already tried, and failed, to run a country on similar ideas.
The invisible hand, in its actual context
Most people associate Smith with the phrase 'the invisible hand'. It appears once in the Wealth of Nations, in Book IV, Chapter 2. Smith is arguing that a merchant who chooses to invest capital domestically rather than abroad is led by self-interest to 'promote an end which was no part of his intention'. The end is national capital formation.
Smith is not saying that all self-interested behavior produces public good. He is describing a specific, limited case in a chapter arguing against mercantilist trade restrictions. The phrase has been generalized into a theory of unregulated markets it was never meant to support.
What Smith was actually worried about
Smith spent significant portions of the Wealth of Nations warning about corporations, cartels, and the relationship between businesses and the state. A famous passage in Book I, Chapter 10: 'People of the same trade seldom meet together, even for merriment and diversion, but the conversation ends in a conspiracy against the public, or in some contrivance to raise prices.' He believed the joint-stock form of business (the ancestor of the modern corporation) was unstable and generally a bad idea except in limited cases.
His suspicion of merchants running the state is stark. In Book IV, Chapter 8: 'The interest of the dealers in any particular branch of trade or manufactures is always in some respects different from, and even opposite to, that of the public.' He saw regulatory capture before the term existed.
His earlier book matters
Smith published 'The Theory of Moral Sentiments' in 1759, 17 years before the Wealth of Nations. It is a book about sympathy, conscience, and the social bonds that make markets work at all. Smith saw the two books as complementary. You cannot read one without the other and get him right. Markets, in his actual view, only function inside a moral and legal framework that constrains the worst impulses of their participants.
Treating Adam Smith as a cheerleader for pure unregulated capitalism is a modern invention. He was a moral philosopher writing about how commercial societies could be stable and just. The answers he gave were more conditional, and less cheerful, than the ones often put in his mouth.