This one. I’m a terrible draftsman. I’m a visual artist by trade (photographer), but just terrible at drawing. BUT … I picked up this book my senior year in college, and within a couple of months (and not practicing a hell of a whole lot), I was able to draw a convincing shaded pencil portrait that I would not have thought possible before I read that book. It was more about the mindset of drawing and seeing more so than actual technique, though it does contain exercises and things like that. It really taught me how to see and how to draw what I see, not so much what I think I see and what I think things should look like. I know that sounds a bit psychobabbly or something, but it really clicked with me.
For me, it’s really the place to start to get into the mindset of drawing rather than specifics about certain techniques. That you can expand upon later. Seriously, for me the book was nothing short of mind-blowing. I’m not going to guarantee you’ll have the same results, of course, but it was exactly right for me (and evidently other respondents in this thread.) It’s not necessarily great for drawing from your imagination, but that’s another skill that can be developed afterwards and drawing from real life or photos helps a bit. It’s one piece of a greater puzzle, but I would start here, even if abstraction is your jam (and it actually is mine, but I’ve always wanted the ability to draw a passable simulacrum of reality).