The section on ISBN was super critical for me personally.
It's great to see the amount of resources he posts for free on the blog / Twitter without locking them away. Thanks Arvid!
I've always found the indie hacker/bootstrapped founder community to be very open and supportive. Many of the people who wrote the guides and articles that I learned lots from have never paywalled their content. If at all, they added some sort of additional product, a course, a book, or consulting opportunities. But the content was always free for those who'd need it most. And that's what I wanted to do as well.
Amazed by the his results. Personally I haven't read the book but some of my friends have and their review was pretty positive.