Some books have actually caused harm. The one good book I read and reread is "Trading Rules that Work: The 28 Lessons Every Trader Must Master" though there are parts of the book I did not find helpful there are some very important points: Order flow and only order flow is what moves markets Know your time frame There are other good books that come to mind but this is one that is overlooked.
What I always tell people who have read technical analysis books and think they know it all... "There's a big difference between looking a chart and actually trading."
They are useful in the sense that you must know how common traders get trapped, when and how they begin to feel pain.
To "know" is to be directly experienced by oneself.....hence by reading alone, one cannot possibly know. Actually, I've never read a single book on trading.....nor does one needs to.
As far as actual trading goes, there's a maximum of 5 books I'll say that helped me. As of late though, I've been reading mostly books that deal with mindset and stories about trading and traders. Books like: More Money Than God, When Genius Failed, The Big Short, etc.
I think practice helps more. Sometimes it's just analysis that no one can write in a book. You just know where price is going and are able to take the trade. The reason is that patterns discussed in books do not show themselves on the right side of the chart exactly like the book shows happened in the past. It can be similar and with practice you know what is happening. For example, you keep a journal and write down what happened after each trade. What did you do right or wrong. The goal being you stop making the same mistake. Here is an example, yesterday I thought that price would go up, but I only wanted to get in the trade after price had already gone up for awhile. The problem was that even though price continued to go up after I was in the trade, I got in so late that my target was not hit, and price reversed and hit my stop. Today I thought based on PA and TA that price would go down. I still waited for price to start moving in my direction by a couple ticks but I was able to get in much sooner and target was hit. However, I did take heat on this trade, price came up close to my stop after getting into the trade before going back down, but I did not panic and kill the trade. Now the goal is increasing the number of contracts I am trading.
Of the 200 plus books I have read, three are on my desk and 2 of them I reread each year, all three written before 1980, so they deal with Price charting. I do use indicators have rules to reduce possible losing trades. Some books became firewood material as they never offered even a tidbit of useful info for me nor did they give me an idea of doing something else, some books are so heavy they been useful keeping office door from closing, Tharps material. I have found all the psycho books to be useless for me, in order for anything to help, you have to believe and I simple don't or won't believe in some concepts. We all have our ways of pain to overcome to achieve our Goals.
I didn't read much books but I read a lot of material on different forums and on some trading teaching websites. I've gained a lot of knowledge from all this. Currently my only problem is risk management. When I see a good setup I follow it with big lots aiming to get more from it but eventually lose a lot.
How do you know you have gained a lot of knowledge? There's no knowledge until you become consistently profitable. You could think it's knowledge, when it's just garbage.