It is a foundational work of political philosophy and political economy, and it is an influential though now very outdated work of economics. If you have an interest in later economists or theorists of political economy (Ricardo, Marx, Hayek, etc.), they are all in some way building off of the ideas of Adam Smith.

If you are someone who invests “free markets” with some sort of totemic significance, I think actually reading Smith is a useful corrective. He’s writing at a time when “capitalism” (as, somewhat ironically, later socialist thinkers would deem the system) was just developing, so he doesn’t have quite the ideological investment in the system that later folks would.

Here’s Smith on taxation, for example:

The necessaries of life occasion the great expense of the poor. They find it difficult to get food, and the greater part of their little revenue is spent in getting it. The luxuries and vanities of life occasion the principal expense of the rich, and a magnificent house embellishes and sets off to the best advantage all the other luxuries and vanities which they possess. A tax upon house-rents, therefore, would in general fall heaviest upon the rich; and in this sort of inequality there would not, perhaps, be anything very unreasonable. It is not very unreasonable that the rich should contribute to the public expense, not only in proportion to their revenue, but something more than in that proportion.

Now, that approach to taxation would obviously lead modern Republicans to refer to him as “radical leftist Adam Smith,” but this is actually what Adam Smith thought about the issue of taxing the rich. Marx was actually quite a big fan, and in many ways saw him as essentially building off of what Smith had done.