The main idea of the book is that children who don't turn in assignments, don't clean their rooms, lose their belongings, etc., often do so because they suffer from executive skills deficits. Consequently, telling them to try harder, yelling at them, punishing them, and so on simply won't work: the children don't have the skills to do what you're asking. You need to solve the problem by teaching the skills instead of just getting mad about the symptoms of the problem.
Unfortunately, the authors fall prey to exactly the kind of thinking they warn the reader about. For example, when writing about kids who cry over little things (lack of the emotional regulation skill), they say:
"Let your child know that crying too much makes people disinclined to spend time with him or her. [...Tell them,] "When you use words, I'll listen and try to understand your feelings. If you start to cry, though, you're on your own. I'll either leave the room or ask you to go to your bedroom to finish crying.""
Really? A child is crying because they *don't have* the executive skills to express frustration and disappointment another way, and the plan is tell them that nobody likes them they way they are and then punish them by withholding affection? As it happens, I *was* one of those kids who cried a lot, and reading that section made me feel nauseated. Thank goodness my parents had some compassion, apparently unlike the authors.
In addition, the book is very repetitive and most of it is taken up by sample interventions. I would read parts 1 and 2 and skip the rest of the book, or only read chapters that address a skill you're really interested in helping your child improve.