The Mystery of the Burnt Cottage
By Enid Blyton
Methuen & co. Ltd., 1943
The Mystery of the Burnt Cottage is the first book of The Five Find-Outers and Dog series, which would eventually comprise 15 volumes. It is a mystery novel for children in the general range of 10-14, and is somewhat politically incorrect by today's standards, although less so than some of Blyton's books.
Larry, his little sister Daisy, and their friends Pip and Bets are intrigued when a neighboring cottage burns down. The fire is exciting enough, but soon the police determine that it was arson, and the neighbor had some very valuable papers lost in the fire. They begrudgingly team up with some rich toff, AKA Fatty, who is visiting for the holidays -- they mostly accept his company because he has a dog, and detectives should have a dog. Together they become the Five Find-Outers. Which is to say, detectives.
They soon learn that the household had been very busy that day; the cottage was a used as a workroom for a rather wealthy man, and most of his staff has reason to dislike him. He'd also argued with a colleague that morning, and a tramp had been sneaking about as well. This mystery focuses mostly on tracking down and interviewing suspects, but there's plenty of sneaking about gathering clues as well.
This is a good, fun mystery, but is at times a bit rough in tone by today's standards. The kids immediately taunt Fatty for being fat, giving him the unwanted and permanent nickname of Fatty; they privately think that he is plump, conceited, and stupid, and quite openly punish him for this (in their defense, he is quite conceited). Bets, who is only eight years old (and a very young eight, by today's standards) is treated as a useless bother. Also, while the mystery is satisfying, the kids have a lot of lucky breaks, to the point of deus ex machina.
While this is the first book in the series, it may not be the best place to start; the writing is a bit choppy and underdeveloped, and you don't really miss anything by starting mid-series. It does give some context to the whole series, as it describes the Five's founding, and explains odd little mysteries like, 'why the find-outers, for god's sake?' (Bets was just eight, and didn't know the word 'detective'). If you enjoy the series, you will want to read this book, but don't make a particular effort to start here.
The next book in the series is The Mystery of the Disappearing Cat.