There is a proverb that tells us, knowledge is like a precious jewel. Get it, and sell it not. Knowledge becomes truth that "will set you free!"
You can pay an auto mechanic $400 to fix your car...but if you had the knowledge, a $40 kit at the auto center would have saved you $360 minus your time invested...
If you've got time, but you're tight on money...then that knowledge has set you free...
Those of us wanting to learn to paint from the "pre-" internet days...lived a life more or less requiring the reinventing of the wheel. Banging our heads against the wall with the frustration of elusive understanding....
We looked forward to exhibitions and shows with our peers with expectation and hope that a bit of talk throughout a weekend, and someone might open up and share how he/her managed to pull off a technical thing.
Today...we are much spoiled. A bit of a search engine query...and you have a gazillion possibilities to wade thru.
Choice is one part of it...but then are varying camps of thought, with one that fears that any influence that originates outside of one's self somehow binds and coerces the unsuspecting weak willed individual to wake up one morning and find they have evolved into someone other than themselves, painting like another.
Funny thing is...who can put a finger at any one moment on precisely who they are?
I like Alan Watt's quote..."defining yourself is like your own teeth biting themselves"
We spend so much time worrying about such its ridiculous...IMO
A book should not be a perceived threat. It is a peer...for whom you do not have the convenience of time and place to hang with and get to know on a personal level. Opening up and sharing with you.
Like any opinion a friend gives in private...you are free to dismiss it. As I oft say, opinions are a bit like armpits... everyone has at least two of them, and most stink!" ... but...having said that, we celebrate the advent of the internet for the reason we need not live in isolation as in the days of old, nor reinvent the painter's wheel as was custom.
Anyone who thinks different wasn't producing professionally as an artist back in the day...
So...simply look at a book for what it is...an artist's thought you are free to consider or dismiss. Someone you meet at a show, or have a chance to paint with.
As an art instructor...I have written my own, working on a new one and have several videos out. I sometimes buy paint/art books simply because I like the layout, and am critically looking at how the book is designed, the content covered and so forth. Sometimes I do that even though the artist's work may not be to my own personal liking.
One such book is one I picked up recently from amazon.com by Michael Albala-
I would say...Michael's book is one of the most comprehensive really, covering so much of everything. A bit of John Carlson's knack for speaking to the painter too...a teacher's teacher.
I have so many books on my shelves, that I have them going back one row against that of those behind them, and then others laid on the flat sides atop.
Its like someone saying, "what is your favorite color?"
Heck...I don't believe I have a favorite color. My pigments used are essential in what they all bring to the table and allow me to execute, but my favorite color if I had to pick...is the one I need at the moment.
Books...ideas, teaching...should be understood to fall along that same line of thinking. We learn in bits...pieces, and bridges are built connecting the past to the present. A good thing our brains don't require defraging...imagine how long that would take!
Instead of looking at the $30 to $45 or more for a book or video as ridiculous or out of the question...look at yourself living a long time and that you are worth investing in. Fill your own cup to overflowing so you have something amazingly wonderful to share with others!!!