This was a gift from my life partner. I like the neologism "bonus parent", but I'd rather be "adult friend" than "bonus dad".
The book is organized by situations or issues that can occur in patchwork families.The book points out possibilities that I would not have thought of myself, and it points out preconceptions or misconceptions that perhaps many people -- including me -- have.
Still, something makes me not give the book full marks. It leaves me wanting to read more; it remains an introduction.
Another point is that the translator seems to have failed to alternate between genders. (I have read the German edition).