While the book contains beautifully hand-drawn imagery, it romanticizes & reinforces the common anti-Catholic myth about Galileo that the Catholic Church "persecuted him out of fear for his scientific work."
What the Church actually tried Galileo for, simply put, was his insistence on teaching his scientific theory regarding heliocentrism as though it were a dogma; as an article of the Catholic faith.
Initially, the Church lauded his findings and the Pope at the time even recognized his findings and even gave him an audience to compliment him on his work.
Galileo was essentially trying to out-compete his scientific competitors by using the fact that the Church recognized his findings as a trump card. He tried to get the Church involved in his personal competition against other scientists.
The Church refused & ordered him to knock it off. He didn't. Eventually, he was sanctioned, warned, then finally tried & given the punishment of house arrest in a luxurious mansion.
While this book is very pretty to look at, if you do read this to your children, please give them the facts of what really happened afterwards and tell them that this is why doing your research is important.