The Hardings are homeschooling parents who have prepared their children to start college by age 10-12. The book is written by both parents and contains essays written by the children.
If you think starting college before puberty is a good idea, the lack of organization, stylistic infelicities, generally poor writing skills, and illogical positions that pepper this book will convince you otherwise. I've reviewed over 1,000 books on this blog and I'd be hard pressed to find a half dozen that were as poorly written as this one.
The temptation to do a line-by-line response to this book is great, but I'm going to resist it because it just isn't worth the time. I will mention how jarring it is that they pivot from describing how terrible classroom-based instruction is to how quickly they encouraged their children to enter into it, from the financial difficulties of paying for college for ten kids to references to children taking intermediate algebra and Spanish in college, from the importance of spending time as a family to having mid-teens live away from home and pre-teens in college during the day. I will also say that they remind me of people who seem very proud that they traveled all the way through Europe in just three days, without considering that there might be some benefit to slowing down a little and spending more time exploring instead of trying to set a land-speed record.
If this book were simply describing their family's personal experience, I would hesitate to criticize their choices, but they are advocating this unusual path. It is a terrible idea explained in a terrible book.