This is a book that makes you grin from ear to ear. On one level it is a story of breath-taking magic, of crunchy chemicals in glass tubes that can make you fly, or invisible, or swop bodies for the day with your posh Scottish step-brother, or make toffee-bars come to life and wrap themselves over warm radiators in the middle of a posh dinner party. On another it is about trying to squeeze two families into one and how you can't expect two sets of children to get on just because the adults happen to have fallen in love. This secondary theme is so apt for modern life, it is hard to remember that Dianne actually wrote this book back in the Eighties. It is funny, clever, magical and touching.
And it has as a central figure, Caspar, a character every bit as wonderful as Eric Chant. Caspar is wise and cool and ridiculous all at once, a child version of Bill Murray's Peter Venckman from Ghostbusters. Caspar steals every scene he's in and is one of those characters who you long to be real so that you could spend time with him.
A cracking read and one that is just as good if you are in your mid-thirties as it was when you were eleven.