"Hooray! It's my birthday!" is a fun children's book that makes incredible birthday wishes come true: It was supposed to be a perfectly normal birthday. But suddenly, everything changes! Together with their funny Uncle Theo, Robin, Jakob, and Klara experience a completely crazy day. A treasure hunt leads the children to a deserted island. But the exciting search isn't the only adventure for the little explorers. Many more surprises await Robin and the birthday guests…