Bōkyaku Tantei (Japanese: 忘却探偵, lit. "The Forgetful Detective") is a Japanese mystery novel series written by Nisio Isin and illustrated by Vofan. It has been published by Kodansha since October 2014 under their Kodansha Bungei label. A manga adaptation by Yō Asami titled Okitegami Kyōko no Bibōroku (掟上今日子の備忘録) was serialized in Kodansha's Monthly Shōnen Magazine from August 2015 to March 2017. It was collected in five tankōbon volumes. A Japanese drama adaptation also titled Okitegami Kyōko no Bibōroku aired for 10 episodes on NTV from October to December 2015.