The Tegos Tapes is an interesting example of an obscure and heretofore unreleased Vangelis soundtrack unknown by many of even his most devoted fans.
The Tegos Tapes were produced originally by the Greek medical professional Dr. Stergios Tegos, and contain educational examples of his microneurosurgery work. This VHS set of tapes was not intended for general release to the Public as these training videos were mainly intended for student surgeons in training or offered to other microneurosurgeons via Dr. Tegos exclusively.
Dr. Tegos asked his close friend Vangelis to create a background soundtrack to accompany these videos and Vangelis agreed, composing nearly 8 hours of some of his more pleasing and ambient music. Dr. Tegos thought that a background musical score composed and performed by Vangelis himself would ease the monotony and dryness of the subject matter and help the viewer to focus more effectively.
This music was lost to obscurity for years because of the esoteric and hard to find nature of the videos. Now they have been ripped from the original content for all to enjoy. The voiceovers of Dr. Tegos have been removed and you will only hear pure Vangelis.