I really should read more Agatha Christie! This is the second book I've read and she's so far not disappointing me. In this case though, I listened to the audio book, and loved it. Samantha Bond's narration was very enjoyable, and suiting to be read as the main characters were predominantly British females.
The story was easy to follow, and several characters had a part to play without losing touch with who's who. (Normally I don't like too many characters in one book to follow.) But each one had a purpose and each one was remembered as I read (listened) on. Slightly chilling, and never really a lull, following Tuppence on her clue-finding mission was enjoyable from start to finish.