I'm instead interested at learning about the systems at play with the stock market as the whole thing has always confused me.
Books/Articles/Online Courses will be appreciated!
Avoid pop finance books that is light on numbers. If you want to understand the qualitative aspects/culture/history, books like Flash Boys or Flash Boys: Not so fast are more than sufficient. Stay away from "technical" books that are designed for layman and non-technical readers. They will handwave Black Scholes and economic math and you will simply be going through the movements without truly understanding.
Books like Reminiscences of a Stock Operator are great secondary books to supplement your primary readings. You don't give a beginning programmer Pragmatic Programmers/Clean Code/Programmers at Work when he or she can barely write a hello world, let alone a quicksort. You want a intro to programming course followed by something like SICP to lay in the foundations of abstraction and computer science. It is the same for finance. Half of the books in this thread are either financial pop science or has little relevance to somebody who wants a rigorous understanding of how the stock market system works.
Also to note, Buffet and A Random Walk Down Wall Street are books that espouse certain schools of thought on managing portfolio. Judge them by their history and backtest their theories rigorously. It is like Object Oriented Programming, fads wax and wane with time and everyone has their opinion on how trading should work so take things with a grain of salt. Lastly, trading and managing a 10 billion dollar fund is quite different from e.g. 100k in your tax free social security account due to stuff like network effects and doors that can only be opened when you have enough zeroes on your spreadsheet so what's good for the goose is not always great for the gander.
Once you are done with stock markets, get a macroeconomics textbook to understand how it ties into the federal reserve (or central bank) and how government bonds affect liquidity, that sort of thing. Again, avoid pop science books which shows up way too often on HN (this is worse with biology, another subject that this forum has a poor grasp of).
Excluding some of the technical details, specifically related to US Equities, which are a bit outdated, it is hands down the best book on the subject of market participants and their interactions.
Books like Reminiscences of a Stock Operator are great as well because they provide a little historical context to market regulation and improvements to market structure.
If someone were particularly interested in clearing and settlement there is also After the Trade is Made
that should get you started
Many here have mentioned "A Random Walk Down Wall Street"; let me add that there exists a book called "A Non-Random Walk Down Wall Street", but I haven't read it yet.
Browse Wikipedia on any trading-related topic you find interesting and you are probably going to find some books, such as "The Quants" https://en.wikipedia.org/wiki/The_Quants
Finally, you might want to check out the works of Jack Schwager , Michael Lewis  or Ed Thorpe .
Trading is kind of like that. Long-term value investing, portfolio management, day trading, options trading, quantitative strategies, high-frequency trading, etc, are vastly different approaches, ranging from "assembly" to using a drag and drop website builder. All these can be used to make money, but what you need to know, and how you approach the problem, is different. Books will be useful for one, and totally useless for other approaches. Just like an assembly book won't teach you how to make a website.
You may want to think about what "kind" of trading you're interested in, and then ask for specific recommendations related to that. Otherwise you will just get people recommending random stuff they have some personal relationship with, like recommending SICP to learn programming. Looking at the answers in this thread, this is what's happening. They are all over the places at different levels of abstraction.
EDIT: Also, few people explicitly make these distinctions. Most traders I've talked to are "locked into" their approach and will talk about it as if there were no others. That's becuase of the bias they have. E.g. someone trading on fundamentals may talk to you about earnings reports but will likely not even be aware of techniques using ML models to optimize order execution or fancy order types. Just like many web developers will not be aware of how TCP/IP works, but only vaguely know that it exists somewhere.
Ignoring the 'anyone can make money' byline, a lot of the book covers how it all works. Of all the trading books I've read, this was the easiest one to follow, and the only one that I actually remembered what I'd read afterwards.
As a first step into online trading, I wholly recommend it, although I wouldn't follow his tips verbatim, and your mileage may vary, also do not bet with money you can't afford to lose, etc. ( https://www.begambleaware.org/ )
One Up on Wall Street, 2nd ed. Lynch, Peter - explains what i think is a good way of looking at the stock market
Common Stocks and Uncommon Profits by Philip A. Fisher - shows importance of having investment philosophy
Ahead of the Market: The Zacks Method for Spotting Stocks Early - by Mitch Zacks - shows the importance of quarterly earnings
The Five Rules for Successful Stock Investing: Morningstar's Guide to Building Wealth and Winning in the Market - how to perform proper analysis on company
How to Make Money in Stocks: A Winning System in Good Times and Bad by William J. O'Neil - shows example of growth/momentum investing
Graham, Benjamin and Jason Zweig (2006) The Intelligent Investor, revised ed.
I would also suggest the following books, which offer more in-depth analysis of financial markets and securities:
Henwood, Doug (1997) Wall Street: How It Works and for Whom
Lynch, Peter and John Rothchild (2000) One Up on Wall Street, 2nd ed.
Mishkin, Frederic (2018) Economics of Money, Banking and Financial Markets, 12th ed.
The Five Rules for Successful Stock Investing: Morningstar's Guide to Building Wealth and Winning in the Market
The reason I recommend this is because it teaches you how to read IFRS Financial Reports and calculate Discounted Free Cash Flow, with practical examples.
Fun fact: many people have asked me over the years what my secret to investing was, and I've always pointed them to the book, and told them it's basically just about reading and understanding each line the financial reports. It takes a lot of time to do this, and you have to do it every quarter, for all stocks you own, want to own, and keep an eye on. With time you will learn what sections to skip and it gets faster, easier. But you have to get your information from the reports themselves. To this day not even one of those people has followed my advice and read the book. I guess the thought of putting in effort scared them away as they were also asking me if they can find the reports summarized on some website and use that as their source if information, or if they can pay for some service to calculate discounted free cash flow for them. To me, having the summary and calculation alone is pointless, and it's also the fastest part of the process. What's important is to understand the reason behind the data in the report, something which the summary eliminates. I have not yet attended a Shareholders Meeting for any company, but this also helps with understanding the reasons behind the data.
Yes, to be fair I was skeptical at first as well, the title does look like click-bait. But it was recommended to me by somebody that I trust knew what he was talking about, after that person gave us a talk about the stock market's financial reports and shareholders meetings. I guess the down-votes I got were because of a similar reaction from others, I'll have to keep in mind to write a disclaimer next time I recommend it.
By the way, if you get around to reading it, please drop me an email if you'd like to discuss about the content or need extra clarification on certain topics, or more practical examples (you'll find your way to my email from my user profile). I know I needed in the beginning and couldn't find anybody to talk to since I was the only one in the group that read it, and I was too embarrassed to ask the "mentor" such trivial questions.
The Conceptual Foundations of Investing - Bradford Cornell
True story: A senior trader on the trading desk asked me - "Why did the market go up yesterday?". I tried to pontificate away at some explanation and after a while just shrugged and said - "I really don't know", fully expecting to be commended for my honesty. The trader laughed and said: "The market went up because there were more buyers than sellers". Next question, "Why is the market going down today", he continued "Because they are more sellers than buyers". The whole machinery of finance exists to give you a better story around this but nobody really knows.
There are two perspectives to understand finance. We will call the two perspectives the Alien Scientist and the Blob ;)
The Alien Scientist perspective is that you have arrived at a new planet with a thriving civilization unlike your own and they act in inexplicable ways. After a period of observation, you can predict the outcome of the behavior in the long term. You cannot predict why the outcomes happen. You also cannot predict behavior in the short or medium term.
The Blob is one of the many beings who populate the planet under observation. The Blob is actively trying to understand their environment and how their fellow blobs behave so they can predict the outcomes and thrive from it. The Blob is equally vested in understanding the why of the behavior of their fellow Blobs and also the interaction of the environment, the blobs and so forth (i.e. second, third, fourth-order effects).
You can take the approach of the Alien Scientist (long term investor) or you can take the approach of the Blob (trader/economist). If you take the investor (Alien Scientist) approach you are more concerned with the long term outcomes in financial markets and not with the why (aside: most financial market information is pure noise). The Alien Scientist approach should start by reading "A Random Walk Down Wall Street" and books by John Bogle and Warren Buffet's musings on investments. You would also do well to understand the various tax structures and treatments available to you - 401k, housing, .... since these can significantly impact your end outcomes.
You can invest all the time freed up not having to study finance by reading gossip rags and watching reality shows - you will be entertained and there are pretty people to look at ;) Or invest it in your wellbeing and your long term earning power (i.e. career).
There is plenty of advice in this thread on the Blob approach if you want to go that route.
Buffett: The Making of an American Capitalist by Roger Lowenstein