The greatest singer-songwriter of the twentieth century was Murray Head. No, I hadn't heard of him, either, until I spent a week in France in 1979. Nowadays, most people think of him as a one-hit wonder because of the huge success of the single One Night In Bangkok. A pity because that song is rubbish, it wasn't written by Murray, and he doesn't even sing on it.
If you want to hear Murray at his best, you need to buy The Big Four: Nigel Lived (72), Say It Ain't So (75), Between Us (79) and Voices (80). I've included a link to Say It Ain't So Joe, probably the best song ever written.
After several disappointing albums (inevitable given the standard of the Big Four), Murray finally came back with the brilliant Tête-à-Tête in 2007, together with Crystal Heart, probably the second best song ever written. Though this is pure speculation, I think it's a fair bet that TaT hardly sold any copies.