51 years ago today, Irish singer-songwriter Gilbert O'Sullivan released his iconic single Alone Again, Naturally, which tells a rather sad tale of a lonely man being left at the altar and then telling the listener about of his parents. The song connected with listeners on various levels: the downtrodden could commiserate with the singer, and the lucky ones who were not in this position were reminded of their good fortune. It sold 2 million copies, spent six weeks at the summit in America and earned him three Grammy Award nominations. It was the second best-selling single of the year in America behind Don McLean's "American Pie." Theories about the biographical meanings of the song have been around ever since, so today we take a look at the story behind one of the most famous songs of the 70s.