What are your favourite non-fiction books from childhood?

Is the internet killing children's non-fiction? As children's authors call for publishers and libraries to keep faith with facts , we're reflecting on the titles from yesteryear which brought children a world of discovery. So tell us: which non-fiction books did you enjoy as a child? Was it Anne Frank's Diary , or the Guinness Book of Records, Gombrich's Little History of the World or a favourite encyclopedia? All reminiscences in the thread below, please.