The Personal MBA, a highly recommended business book for Indie Hackers is on sale for Kindle right now. I already own it, but I thought others might be interested!
https://www.amazon.com/Personal-MBA-Master-Art-Business-ebook/dp/B0046ECJ8M
From IH Podcast Episode #49 description
Josh Kaufman (@joshkaufman) has read a lot of business books. He also happens to be the author of The Personal MBA, easily one of the best business books in existence. In it, he lays out the fundamental concepts that are core to every successful business, and in this episode, we talk about how he became the kind of person who was able to write this book.