With tracks like the joyous "Rydeen", the cool "Behind The Mask" and the insanely contagious "Absolute Ego Dance" also on the album, "Castalia" comes across as the cool-down respite of the album. The Professor, Ryuichi Sakamoto（坂本龍一）, came up with the track that had been supposedly inspired by the 1972 sci-fi film, "Solaris" adapted from the original Stanislaw Lem novel about a sentient planet. However, the direct influence was from the music of late composer Toru Takemitsu（武満徹）, known for his innovative fusion of Oriental and Western elements.
"Castalia" struck me as this eerie but beautiful soundscape when I first heard it as a teen, and made as deep an impression on me as "Rydeen" did. It felt like lying down on top of a flat roof of a building in the middle of nowhere at midnight and watching the stars whizz by. It did and still does make for some universe-contemplating thoughts during its 3 minutes and 30 seconds.
Perhaps "Castalia" might make for an aural palate cleanser before that slice of apple pie for dessert?