Ten-year-old Felix is a renowned storyteller; in his world, things happen for the most extraordinary reasons. And it is his voice that leads us through Morris Gleitzman's acclaimed two-part novel - published as a single book for the first time in this edition - set amid the extermination of Poland's Jews in the early 1940s.

Nazi officers arrive at Felix's orphanage, there to burn the contents of its library, and the young narrator determines to save his parents' bookshop from a similar fate. He ends up exploring the darkest corners of the Nazi occupation.

Gleitzman's sense of pace is assured, and such is his ability to handle comedy as carefully as tragedy that it is impossible not to root wholeheartedly for Felix on every page.

Reading both parts of the novel together, one comes to see just what an accomplished creation Felix is. In Once, he consumes the world through the prism of the books that his parents gave him; in Then, he is forced to form his own sense of the horror of the world around him.

Penguin, 246pp, £7.99