I label this as a worthy non-fiction book, but this is sometimes in a loose sense because there seem to be some stories in it where fact and fancy have not been adequately discriminated, but overall I enjoyed it. It makes for a great restroom book because although there are three hundred pages of short (some longer, some very short) stories of the origins of various things, ideas, and people, and so on, most are quite short. The stories are eclectic and no attmept whatsoever seems to have been amde to organize them by any method - topic, category, chronology or otherwise.
The stories themselves are fun though, educational and intriguing. They're largely US-centric, be warned, but not exclusively so. They may cover the building of the Great Wall in China, the building of the Empire State building in NYC, the secret marriage of Mae West, the origin of coffee, Ford's union-busting brutality, how they made Superman fly in the Christopher Reeves era, and who made the first parachiute jump.
I found the book entertaining and fun, and I commend it as a worthy read.