Often described as a key moment in the creation of electronic and ambient sonic exploration, for us Perrey's groundbreaking work comes as our earliest-known sleep-aid recording. Pressed by a French "sleep institute," this album was created for hospitals and mental institutions. Featuring the Ondioline, a vacuum based instrument, this album was researched and composed to induce alpha-wave drowsiness. Its lilting melodies and drone worked like a charm for this writer, who can attest to its abilities. A great addition to our sleep-aid collection: more here, here and here.