What a brilliant book!
Key example - first time I ever read this to my 4 year old daughter...
The two parents in the book are arguing and fighting all the time (all very humorously), and their two children, our main characters, wonder if it might all be their fault. As soon as that question was posed my daughter piped up with, "It is!". I was stunned.
Of course on the next page it is explained how, at a meeting of all the kids at school who have problem parents, it was unanimously decided that it is NOT the fault of kids if "their parents behave like 5 year olds".
From that moment on my daughter has agreed with the book every time, and realises that our separation is not her fault.
This is SUCH a classic thing for kids to think, and I am so grateful that this book surfaced this idea in my daughter's mind (it was obviously already there) and then showed her in a very powerful way what the actual truth is.
I also recommend "It's not your fault, Koko Bear". When I bought these two books and read them to my daughter it made an immediate and profound difference to her, how she felt about handover times, etc.