I guess this is most likely a repeat thread but I haven't seen one so I figure it can't hurt. Thinking about making an actual "effort" to get better again and I wonder if other botb'ers have some gems on music learning to share, anything. I'll start of course and probably think of obvious ones I should have included later

Elementary Training for Musicians - Paul Hindemith
Don't be fooled by the title; this book gets horrifically difficult, at least if you're a n00b like me I guess(?). It has an extremely different approach from most rhythm and pitch training books that is highly open-ended and will make you think like a MFer. It's short so you should probably be coming up with more exercises based on it anyway. The forward is also interesting, he basically rips music schools for being too easy (and this was in the 40's o_O)

School of Guitar - Richard Pick
Two volumes that go through 12 keys. Really aimed at classical geeks but anybody who fingerpicks and reads dots would maybe like it. Every key has the usual scale exercises etc. but he also gives you a handful of short-to-medium length tunes to understand the keys and get them under your fingers. When it comes to flat keys, most solo guitar lit is either dry as hell or just shuns them all as plague territory so this is pretty cool to see. They all have charming little names like "on the knoll" and the whole thing is peppered with little drawings and writings that make it a fun kind of adventure to go through. Very cozy by the fire type of music practice...
SADLY, the old edition is hard to find and $$, and for some idiotic reason the recent edition decided to break up the pieces and the scales, and throw out most of the fun stuff... so I can't really recommend it... : (

Mikrokosmos - Bela Bartok
I haven't really gone through this too much but I would like to... I want to say there are 12 volumes? It's a school of piano from extremely basic to quite advanced, and it's not that long, so I have to imagine it's more of a supplement, but it's presented in a way that I really like. It gives you really wide-open and "modern" concepts in a blank, non-scary way, so I think it serves for some healthy mind-opening

elementary training for musicians is really fun but damn it's hard for me!! i never got all the way through it but i want to come back again sometime

the only music book i have is fundamentals of guitar by miles okazaki so i'll talk about that. the book is kind of a similar vibe to elementary training in that the definition of "fundamentals" is here stretched to somehow include single-player polyrhythms, a deep dive into tuplets, an extended treatment of natural harmonics, and some other relative esoterica. also miles is a jazz player so the book is mostly jazz focused (although this only really manifests in the section on tetrads). there are a lot of neat choose-your-own-adventure open-ended exercises that i come back to from time to time. but if you were looking to learn guitar from scratch or learn how to play jazz as someone with existing guitar skills, this isn't what you're looking for, it's not focused enough to be a crash course, getting-started guide, method book or whatever, it's more like a deep and slightly weird resource that you could pick at forever regardless of your skill level

The Theory and Technique of Electronic Music by Miller Puckette

This is the book that really got me into the world of electronic music when I was first starting out as a teenager. I still recommend it to anybody who wants to learn the fundamentals of how electronic music is made.

And there's a free PDF too!
https://msp.ucsd.edu/techniques/latest/book.pdf

I read Effortless Mastery by pianist Kenny Werner last year and really appreciated the sentiments within about letting go of the ego in music making (he's focused on performance but it absolutely applies to composition too). there's a bunch of meditation stuff in there that I completely avoided but the spirit of the thing is valuable for anybody who has struggled with their relationship to the art form and with wanting more than anything to simply "sound good". the whole learn-to-love-the-process thing. I wound up approaching this book from the perspective of having already kinda dealt with this stuff and largely defeated it in my own way, nodding and going "mhm mhm yes", but it was still a valuable thing to read, and might be for you too...

Thanks guys these are great, all going on the docket

Thought of a couple more:

Basic Principles in Pianoforte Playing by Josef Lhevinne
Lhevinne was a master (along with his wife Rosina.) This <50pg. book is really a collection of his guiding thoughts or advice for students I suppose. Really a gem you can read during lunch

They All Played Ragtime by Harriet Janis and Rudi Blesh
The original famous book of ragtime from 1950. First serious attempt to write about the genre. Perhaps slightly infamous now for "historical inaccuracies," but as bad as that sounds, as far as I can tell it's the byproduct of the authors trying to spin a romantic narrative, which they succeed at. It really puts you there and gets you excited, especially because in the authors' time there were a handful of original rag professors still living. Interviews!! Even extends into a great description of the Harlem stride days. Great bibliography. Probably at its worst when describing the origins of the genre; I guess authors always feel like they have to try, for obvious reasons, but it always feels like over-bold conjecture

twentieth century harmony is so good... at its core it's just a list of harmonic things you can do and their outcome. I'm not adept at reading sheet music and I thought it was really useful. I would recommend having some knowledge of tonal music theory though just to understand the terminology.