This is a detective novel series by Keisuke Matsuoka. Detective's Appraisal II Suikyo Reasoning V Detective's Detective II That's it. They were all, as expected, interesting, and I finished reading them all at once. They are used books that I purchased for about half the list price, but the contents are clean, and I was able to read them without any problems. If you understand and agree with the above, please consider purchasing them.