This is perfect Christmas present fodder, which is indeed where I received this. It's a re-release of a book first published in the '50s, and it really is of a completely different age. Despite being published during the core of the Cold War, it's much more The Thirty-Nine Steps than Our Man in Havana. Graham Greene has a strange sense of humour when it comes to spying, I suppose.
The book consists of snippets - both fiction and non-fiction - from espionage mostly around the turn of the century. Germany is generally the main enemy. Bond has a couple sections, and comes across a bit ludicrous. Baden-Powell turns up, and seems both mad and effective. The book is effectively a sampler in a almost-dead genre. Each vignette might cover an important (or melodramatic) scene from some story, and provide a few minutes reading, but would it encourage you to find the full original? Not really, unless you have a fascination for clumsy proto-spy-stories.
So, if it's no good for encouraging you to read more of the genre, and each snippet gives you only an inkling of the associated plots, what's this book good for? On the one hand, I suppose you can look at it as a summary for a genre you probably don't want to investigate too deeply, providing an overview without having to read several source novels. On the other, you can view it as light entertainment - unchallenging reading where there's no Cold War threat, you don't need to learn who the characters are and what's going on, and you know the good guys'll pull through somehow. Just what you want in a bedtime book.