is a song recorded by Japanese-American singer-songwriter Ai, released on June 4, 2008, by Island Records and Universal Sigma. Serving as the fourth and final single for Ai's sixth studio album Don't Stop Ai, "Taisetsu na Mono" was used in a series of commercial tie-ins.
Ai released "Taisetsu na Mono" as a maxi single on June 4, 2008. "Feel for You" and "Touch the Sky" were included as B-sides, however were later included on Ai's seventh studio album, Viva Ai (2009). Two editions of the single were physically released; the limited edition including a bonus live performance track of "Taisetsu na Mono".
"Taisetsu na Mono" was used in a 2008 campaign for Chartis during the 2008 Beijing Summer Olympics. It also was used as the theme song for the American drama series Heroes in Japan.
Ai appeared on music TV shows Music Station on June 6, 2008, and Bokura no Ongaku on June 13, 2008, performing "Taisetsu na Mono."