This book, Josephine Tey's first novel, was published in 1929.
A man, waiting in a queue to see a musical, is killed and no one appears to have noticed the murder or the murderer. Inspector Alan Grant is called in to investigate this baffling case. Unlike some of the later books in the series, this book is definitely a police procedural following Inspector Grant and his team as they endeavour to establish why the man was murdered and by whom.
When the most likely suspect disappears Grant traces him to Scotland where we get to know more about the thoughts and behaviour of this investigator. However when the suspect is captured Grant begins to doubt that they have the right person and now has to prove the innocence of the suspect as well as establish the identity of a killer. One of the interesting aspects of these novels is observing the techniques used by the police to aid their investigations and the time involved in obtaining information so they can continue investigating the case.
The book has been criticised as the crime is solved more by luck than by police investigation but no doubt this may also happen from time to time in real police investigations. As the investigation continues we get to know more about the victim and one of the themes of the book encourages us to question our views of what we consider to be right and wrong.
A detailed review of this title see the post by Margot Kinberg in the blog, Confessions of a Mystery Novelist.