The Book of Us: Gluon – Nothing Can Tear Us Apart, often shortened to The Book of Us: Gluon, is the first extended play by South Korean band Day6 (Even of Day), a sub-unit of Day6 consisting of members Young K, Wonpil, and Dowoon. It was released by JYP Entertainment on August 31, 2020. The album contains seven tracks co-written by Young K and Wonpil, including the lead single, "Where the Sea Sleeps".
On August 6, 2020, Day6's first sub-unit Day6 (Even of Day) was announced.[1] On August 28, an album sampler was released revealing the track list of The Book of Us: Gluon, constituted of seven songs. The EP was released on August 31, 2020. Multiple songs are stated to have collaborations with "Denimalz 3", which Denimalz is a line of Day6 plush merchandise, with Denimalz 3 representing the 3 members present in the subunit. Denimalz 3 act as the main protagonists in the "Where the Sea Sleeps" official music video.
On September 3, the subunit held their debut stage on Mnet's M Countdown and promoted "Where the Sea Sleeps" on several music programs in South Korea, including Music Bank, Show! Music Core and Inkigayo.
^The Book of us Gluon sales:
"2020년 08월 Album Chart" (in Korean). Gaon Music Chart. Retrieved October 8, 2020.
"2020년 09월 Album Chart" (in Korean). Gaon Music Chart. Retrieved October 8, 2020.
