Amália Rodrigues was one of the most popular singers ever, and one of the best, apparently — in 1959 Variety called her one of the four best voices in the world. A veritable ambassador of Portuguese culture, Rodrigues took the “Fado,” a traditional form of sung lament, and brought it to a world that welcomed her and her voice ecstatically. Director Bruno de Almeida takes an uninspired, conventional documentary approach to lead us through her rapid rise to fame in Lisbon in the late 1930s and through her artistic conquering of the world — the Americas, Europe, Japan — into the 1970s and beyond, telling the story of her professional life through old film clips and kinescopes of early TV appearances cut with a contemporary interview conducted with Rodrigues just before her death in 1999. I, uneducated, uncultured American philistine that I am, had never heard of her or her music, which may be why The Art of Amalia left me cold. Her extraordinary singing is haunting and melancholy, reminiscent of Edith Piaf or Billie Holiday, and though Rodrigues mentions in passing the sadness in her life that helped her sing so mournfully, the film reveals very little of the personal life that influenced her. Was she ever married? Did she have children? Did she lose someone she loved dearly? What made her so sad, and her music so darkly enchanting? The Art of Amalia is cut down from a five-hour Portuguese TV series — maybe the answers I want are on a cutting-room floor somewhere.