What isn't Brian Eno? A musican, and artist - with solo credits and guest credits with many bands, and a much desired producer. As a composer, his music has appeared in films(Trainspotting, Velvet Goldmine, Heat), television programs and commercials. You may not realize this, but the startup sound in the Windows 95 operating system was actually 'composed' and credited to Brian Eno.
As a composer/musician, Eno has created the following types of music: Songs, Instrumental and/or ambient compositions, and experimental. Frequently elements will mix in his albums though for the later part of his career, his output is generally described as Ambient.