Atelier Iris ETERNAL MANA Original Soundtrack / イリスのアトリエ　エターナルマナ　オリジナルサウンドトラック / Atelier Iris ETERNAL MANA Original Soundtrack

Although, the OST contains no individual composer credits, the following composer credits have been provided by:

Atelier Iris ETERNAL MANA Arranged Tracks DECEITFUL WINGS
Atelier Series Vocal Collection ~ Volkslied
Atelier Series & Mana-Khemia Vocal Collection VOLKSLIED 2
Atelier Iris Eternal Mana Soundtrack Diary (http://shop.salburg.com/product/irisCD/diary.html)

Composed by:
Akira Tsuchiya (Disc 1: 1, 2, 5, 39. Disc 2: 39)
Daisuke Achiwa (Disc 1: 4,  8,  37. Disc 2: 16, 20, 22-25, 35, 38)
Ken Nakagawa (Disc 1: 6, 7, 12, 25, 28, 38. Disc 2: 1, 2, 4, 5, 10, 11, 14, 18, 30)

All other tracks composed by either Daisuke Achiwa or Ken Nakagawa (Tsuchiya states in the Soundtrack Diary that he only composed Byakuya Gensoutan, Genesis and IRIS)

DISC 1: 1 & 39  
Lyrics/Composer : Akira Tsuchiya
Arranger : Akira Tsuchiya/Takashige Inagaki
Vocal: Haruka Shimotsuki

DISC 1: 38
Lyrics/Composer/Arranger : Ken Nakagawa
Vocal : Mami Horie

DISC 2: 38
Lyrics : Kanae Aoki
Composer/Arranger : Daisuke Achiwa
Vocal : Mami Horie