: Unknown or Stranger) is the title of the fourth studio album by Spanish singer Marta Sanchez (in 1998).

The album was produced once again by Christian De Walden and a few Italian co-producers.

[1] The singles were "Quiero Mas de Ti", "Desconocida", "Los Mejores Años de Nuestra Vida", "Estrellas de Fuego" and "Loca de Amor".

The album is dedicated to the late father of the artist, and it sold 600,000 copies worldwide.

The English version is called Perfect Stranger.