Rather than simply using the number "4," we have titled this volume "for" to express our deepest gratitude to all the fans who have supported YOASOBI throughout the journey of "THE BOOK" series. This album features original illustrations of the duo, Ayase and ikura. The artwork was designed by Nina, an animator who has been a long-time supporter of YOASOBI’s creative vision from various perspectives. The final product will feature the full tracklist and credits.