The Merry & Happy Monograph is a limited-edition companion to TWICE's first repackage album, released April 16, 2018. It documents the production of the Christmas-themed Merry & Happy era — capturing the "Heart Shaker" and "Merry & Happy" music video shoots, as well as the festive album jacket photoshoot, through exclusive behind-the-scenes photos and footage. It includes a 150-page photobook, an approximately 30-minute making-of DVD with Korean and English subtitles, and 9 individual member photocards. Notably, this is the last TWICE monograph to include a DVD, making it a particularly significant piece for collectors who value the complete monograph series.