AM pop was the dominant sound of Top 40 AM radio during the 1960s and '70s. At the beginning of the '60s, AM radio was by far the dominant format; after 15 years, however, that status would shift to FM, thanks in large part to its willingness to play album tracks and longer songs (which earned it a devoted audience in the era of album rock). AM was the more tightly programmed, singles-oriented band on the dial, and it played the sort of commercial pop music that has since become synonymous with the era. Some AM pop singles appeal to modern ears only as embarrassingly kitschy artifacts of their time, far too dippily cheerful (or maudlin, as the case may be) for their own good. But AM pop wasn't just about bubblegum and mellow pop -- there was also room for soul, British Invasion rock, post-psychedelic pop, country-rock and country-pop, folk-rock, and even occasional hard rock (provided it was concise, catchy, and not too heavy). Also, it delivered songs by most of the best acts of the rock and soul era: the Beatles, the Beach Boys, the powerful Motown and Brill Building stables, Neil Diamond, the Mamas & the Papas, and Simon & Garfunkel, among many others.