Best known for his humorous mysteries, Akagawa's first short story, "Ghost Train", was published in 1976 and went on to win the annually granted All Yomimono New Mystery Writers' Prize by Bungeishunjū, a Japanese literary publishing company. Other works of his, The Incident in the Bedroom Suburb (ホームタウンの事件簿 私語を禁ず Homu Taun no Jikenbo: Shigo o Kinzu?) and Voice from Heaven (天からの声 Ten kara no Koe?), were later made into anime, while Sailor Suit and Machine Gun (セーラー服と機関銃 Serafuku to Kikanju?) was made into a popular live action movie. His most recognized works to date pertain to his Mike-neko (or Calico cat) Holmes series. He is extremely prolific; as of August 2006, he had written more than 480 novels in the course of his thirty year career, over 300 million individual published volumes.
This book comprises four short stories by known Japanese mystery writers, four stories that make for a mixed bag, but one that is surprisingly enjoyable if you take into account its simplicity. Not that it is a great compilation, but it is easy to read and more interesting than one would think at first sight.
The book stories, even if it says in the title that there are 'riddles', 'mysteries', have little of real mystery in them, and are more about little silly deductive situations: how did the teenage girl end up sleeping in the lion's den? in which station is the girl waiting for her 'possible future boyfriend'? is there really a golem in the primary school? who is the thief waiting to get all the money in the shopping mall? Not mysteries if you are expecting Sherlock Holmes. And not much deductive power used in them. The stories are simple, there is not much character development, and the storytelling and writing style is simple at best.
However, even if the stories are not 'high quality', they make for an easy read, and a young kid who loves to devour books will enjoy it. It is just there is so much else out there...
The best: the stories are easy to read, and enjoyable for a young reader; the last story has some surprisingly engaging word play with hiragana/kanji (I didn't expect to enjoy it so much; even if it is simple and silly)
The worst: way too simple
Alternatives: Kaoru Hayamine has another detective with great novels (Yumemizu), Edogawa Ranpo, "The Three Investigators" (if you go to English speaking novels), Flanagan (in Catalan/Castilian; a little bit older readers); Carlos Ruiz Zafón novels for teenagers (these are recommended for someone a little bit older than the readers of this book too)... There are many options, many...