Clouds of Witness by Dorothy Sayers

The Lord Peter mysteries are so incredibly entertaining, and I absolutely loved this book too. I adore Lord Peter and his ridiculous behaviour (even polite when drowning in a bog) and his mother, the Dowager Duchess of Denver who, when Peter tells her that she has a detective instinct, replies that 'I'm an old-fashioned woman and I call it mother-wit, and it's so rare for a man to have it that if he does you write a book about him and call him Sherlock Holmes'. I didn't really like the way the mystery was solved at the end, because it turned out that for the solution we had to have more information that was provided, and an extra character had to turn up out of the blue to explain it. I get annoyed by that because it takes the fun out of trying to figure out what happened, and there is no way to know because the solution is not in the book. But I loved the situation; a man is found dead and on the way to figuring out what happened, it's discovered that almost everyone in the aristocratic household has been running around that night on various love- and sex-related affairs, which had nothing to do with the death. As Lord Peter remarks, there are just too many things going on, and it's impossible to take the story seriously. It's a lot of fun, and features an obligatory (obligatory for seemingly any novel set in the North) almost-drowning in a bog and gorgeous woman hidden away in the bleak countryside.