The title is interesting - Change, but the book actually begins with times when people don't change. It suggests that we look to the "solution" already applied. It is usually the more-of-the-same solution. At the end, we discover that problematic is not the problem itself, but denials, utopian myths or paradoxical thinking. Therefore, to change, one has to think out of the box.
Maybe my mathematics is not good. I find it confusing to consider "change" with the group theory. I'd rather skip the theory part and read the practical section alone.
Just a note of caution. I sometimes find the solution that the book provides weird. For example, a mother has her son doing homework by exploiting the boy's hatred towards the principal. She lied that the principal has betted on the boy's failure to hand in homework. Well, homework is done. But what else has the boy learnt?