Philips' Prospective 21e Siecle Records

I can still remember the thrill of discovering a couple of these records in a Parasian flea market almost two decades ago.  From the moment I saw the intricate foil sleeves, I knew there was another sound world waiting to be discovered.  Philips' Prospective 21e Siecle Records was launched in 1967, as a platform for the newly emerging musique concrete and electronic scene.  The covers were printed using polarized metallic inks and still look as futuristic as the day they were designed.  I've tied to research their author but found scant clues.  If you know who designed them, I'd love to know.