This review is for the hardcover "Mk1-MOD1" edition. In short, this is a miniature coffee table book of aphorisms (or short quotes). If that's not what you're looking for, look elsewhere. Jocko has some novel-length training manuals if you want those. This book is very visual, so it's not good in a Kindle edition. Get it hardcover, or not at all.
So what is "Discipline Equal Freedom"? It's a semi-pocket-sized tome of motivation. The idea is to present Jocko's core ideals in a digestible form. Jocko blends stoicism and American patriotism into a some ultra-powerful quips. Things like, "Step. Step. Go. Now." or "YOU WILL WIN". Jocko's hope is clearly that if you read two pages of aphorisms, set the book down, and never pick it up again because you're busy changing your life, that would be "GOOD."
But what is it really? It's black and white. Jocko likes monochrome. You end up with a lot of white on gray, gray on black, and so on. This means the book is not always super high contrast, and that's a challenge for some people. For the average person though it's perfectly readable. It's often white text on a black-and-white photo of something motivational, like Jocko's home gym covered in sweat after a workout. The words are simple and direct. Jocko says why he's doing this in the first pages, and the rest of the book is just supplemental material to the central point - basically, own your life own. Don't wait. Go.
The mk1 edition, if I'm remembering the first printing correctly, seems to have some more readable contrast throughout. It seems like there were some tweaks. There is supposed to be extra content too, but without having them side-by-side I can't really tell the impact. The important thing to me is that I wanted this book, and this is the best edition as of writing.
So it's 247 pages of aphorisms. A picture of Jocko, with words telling you to work out and eat right. I like it. If you need further details, there's plenty of references on what to do on Jocko's podcast and in his other books. He even makes a series of kids books, so his material can suit people of any age. But this book is clearly targeting his adult audience, and people who need some quick pick-me-ups. If you'd like to be able to thumb open a page, and read Jocko telling you to "Grab time by the throat" this is the book for you. Recommended.