What I'm going to write here is largely redundant with what a couple of responses, so apologies to those users as it drives me crazy when people just paraphrase something I just wrote, but this is a thing that has come up so often with students I have worked with and I struggled a lot with it myself when I was younger and just learning.
Having a book of notated scales is somewhat akin to having a list of all the variations you could get in a Tic-Tac-Toe game. Everything in the book might be true but its difficult to become good at tic tac toe by looking at it.
When I was a kid, I would see an article about some scale, and I would memorize some shape that I could use to play it, then I would try to find some piece of music where I could waggle my fingers aggressively in that shape and it would sound like I knew what I was doing, even though I rarely had any idea what notes I was actually playing. I could get paying gigs because I read alright and could play solos that sounded like solos when called upon, but it was just intuitive playing. When I started trying to play jazz gigs the wheels came right off though, so I just didn't play those.
At some point I had that experience of knowing that I was missing something that all these other players knew, but I didn't know what it was. I also wanted to get my upright playing together so I got hooked up with a teacher. We were working on about the least-theory intensive thing you can imagine, butchering these little Simandl etudes with my terrible bowing. However, this guy was primarily a jazz player and every once in a while he would say "by the way, what do you notice about the tonality of this one?" and I would have no idea. He was also meticulous about identifying the key of any tune before we started, and Simandl leaves no key unturned in his method book, and one day he was like, man how can you just have some key signatures that you don't know?
And what he meant really was that he could ask me to play a Bb dorian scale and I could do that because modes were hip, but if he asked me to play Bb melodic minor I couldn't because I didn't know what shape to use for that. Even worse, I couldn't actually tell you what notes I was playing if I played Bb Dorian without looking at my fingers and trying to figure out where they were landing.
I won't bore you with the entire arc of the story between then and now, but the synopsis is that in my haste to memorize a shape in order to play something which gave the impression that I knew what I was doing, I skipped over pretty much the entirety of the basic harmony which, if you lack it, is almost like being unable to read or write your native tongue. This guy was (and still is, my kids go to him now) absolutely relentless in making sure that you had all the boxes checked on the big list of "stuff every bassist should know" and, although scales are on there, they're just a small part of the overall picture and you start with just a couple and then there's a very long road between you and, say, the symmetric diminished scale.
I'll use one of the tactics this guy used on me on you: without picking up your bass or imagining what the fingerboard looks like, what are the notes in the Gb major scale? If you can't do that, you don't know the major scale. I sure as hell couldn't do it and I had been playing major scales in any key for years when he asked me that. But because I had been playing a bass instead of a piano, I didn't have to know what I was playing, I just played shapes.
So the reason I don't like these books of scales is that they are sorta like using Cliffs Notes in an english class. If you read the book, the Cliff's Notes may be very helpful in clueing you into the details of a book that are likely to be on a test, but if you don't read the book, the Cliff notes are just like a hollow shell; it beats doing nothing but what you'll be missing will be a problem down the road.
Some day I should write a complete list of this stuff, but a good starting point is to be able to answer that question I used as an example. If somebody has a deck of flash cards with all the major key names, you should be able to spell the scale, you should be able to tell me where the whole and half steps occur in it, then you should be able to tell me the quality of each triad in the scale (for example, what kind of triad is Gb/Bb/Db? Ab/Cb/Eb?, and so on), then what are the 7 chords for each scale degree? Then do the same thing with minor. Then you will be at a point where the modes of major and minor have meaning not as scales but rather by the function of the diatonic chord formed from that scale degree.
Memorizing all this stuff takes some time but surprisingly not that much assuming you know what stuff needs memorizing and what order to do it in. But its like building a house; if you don't build a foundation right the rest of the thing is going to be rickety, so its better to ask somebody who builds a house than to treat it as an experiment.
Anyway good luck and apologies for the lecture- I only give it because I could have avoided years of anxiety and frustration if somebody had given me a basic harmony exam and made me fill in all the stuff I was missing. I enjoyed playing music 100x more after I found what I was missing, and I'm still a pretty lousy theoretician which should be encouraging.
