To understand the power of free thinking, I recommend reading , “My Bondage and My Freedom” by Frederick Douglass. Here is a free gutenberg.org version, but I have it downloaded on my kindle, so here is the free kindle version too.
Frederick Douglass was born an American slave in 1818 in Maryland and he died a champion of human rights, an abolitionist, a writer, renowned orator, but most of all a FREE man in 1895. (short bio here).
Douglass relates how as a slave, learning to read was forbidden, but a white mistress undertook teaching him to read for a short time, before being reprimanded by her husband. From that point on, Douglass embarked on a secret, dangerous mission to educate himself:
“Seized with a determination to learn to read, at any cost, I hit upon many expedients to accomplish the desired end. The plea which I mainly adopted, and the one by which I was most successful, was that of using my young white playmates, with whom I met in the streets as teachers. I used to carry, almost constantly, a copy of Webster’s spelling book in my pocket; and, when sent of errands, or when play time was allowed me, I would step, with my young friends, aside, and take a lesson in spelling. I generally paid my tuition fee to the boys, with bread, which I also carried in my pocket. For a single biscuit, any of my hungry little comrades would give me a lesson more valuable to me than bread. Not every one, however, demanded this consideration, for there were those who took pleasure in teaching me, whenever I had a chance to be taught by them.”
Douglass, Frederick (2009-10-04). My Bondage and My Freedom (p. 85). Public Domain Books Kindle Edition.
Douglass heard some white boys mention a schoolbook, The Columbian Orator, and determined to acquire a copy. He bought a copy for fifty cents. The Columbian Orator was a popular 19th century schoolbook filled with speeches and essays, geared to promote republican virtues (in other words, good citizenship, if you are living in a republic like the United States of America) and patriotism. To quote Douglass:
“I had now penetrated the secret of all slavery and oppression, and had ascertained their true foundation to be in the pride, the power and the avarice of man. The dialogue and the speeches were all redolent of the principles of liberty, and poured floods of light on the nature and character of slavery. With a book of this kind in my hand, my own human nature, and the facts of my experience, to help me, I was equal to a contest with the religious advocates of slavery, whether among the whites or among the colored people, for blindness, in this matter, is not confined to the former. I have met many religious colored people, at the south, who are under the delusion that God requires them to submit to slavery, and to wear their chains with meekness and humility. I could entertain no such nonsense as this; and I almost lost my patience when I found any colored man weak enough to believe such stuff.”
Douglass, Frederick (2009-10-04). My Bondage and My Freedom (p. 87). Public Domain Books. Kindle Edition.
He continued:
“Once awakened by the silver trump of knowledge, my spirit was roused to eternal wakefulness. Liberty! the inestimable birthright of every man, had, for me, converted every object into an asserter of this great right. It was heard in every sound, and beheld in every object. It was ever present, to torment me with a sense of my wretched condition. The more beautiful and charming were the smiles of nature, the more horrible and desolate was my condition.”
Douglass, Frederick (2009-10-04). My Bondage and My Freedom (pp. 87-88). Public Domain Books. Kindle Edition.
libertybelle diaries 
“Learning to read was forbidden.”
Evil people know the extraordinary power of the ability to read. Progressives have made certain that, in the schools they control, it is nearly impossible for students to learn to read beyond an extremely rudimentary level. And for those who manage, despite the odds, to actually teach themselves to read well, the Progressives do everything they can to limit the value of the available reading materials. Moreover, Progs are always on the alert, ready to silence anything that might be worth hearing.
Those who wish to enslave know how to do it. They have known it throughout history, and that is why acquiring the capabilities of reading, writing, and speech have always been a battleground.
Frederick Douglass is a great man, and a quintessential American. I say “is” because his writing walks with us whenever we wish it, and, once read, lives with us throughout our days.