This is an official commemorative booklet produced to celebrate the 50th anniversary of Tokyo Sogensha's Sogen Mystery Bunko and Sogen SF Bunko (1959–2009). Issued around 2009 as part of the 50th-anniversary commemorative project, this booklet was not for sale and was not intended for commercial distribution. The booklet includes: * A commemorative discussion between Kaoru Kitamura and Kazuki Sakuraba, * Articles reflecting on the roles, editorial philosophies, and publication history of Sogen Mystery Bunko and Sogen SF Bunko within Japanese mystery/SF culture. Rather than a mere chronological record, it delves into: * "What is a bunko (paperback)?" * "What is characteristic of Sogen?" from the perspectives of authors and readers. This is a particularly resonant volume for fans of Kaoru Kitamura, Miyuki Miyabe, and long-time readers of Sogen Mystery Bunko. Although it is an aged item, it shows little sign of use and is in good condition with no folds, writing, or noticeable stains. It is recommended for use as a reference or for collection. \#TokyoSogensha \#SogenMysteryBunko \#SogenSFBunko \#50thAnniversaryOfBunkoPublication \#PublishedIn2009 \#KaoruKitamura \#MiyukiMiyabe \#KazukiSakuraba \#JapaneseMystery \#MysteryReference \#NotForSaleBooklet \#PublisherHistory \#BookLovers