The Beach Boys, The Beatles, The Who, Bob Dylan, The Moody Blues
Popular Music + Pop-Rock + Rock & Roll = Progressive Pop
Progressive pop is a genre known by a few characterizations. One places the genre as a precursor to Progressive Rock. When the two terms appeared in the 1960s, they were roughly interchangeable, referring to a particular style of Pop or Rock music that was more complex and personalized than had been normal for AM radio. Another characterization, most often associated with the 1970s–80s, is thought to bridge the musical elements of progressive rock and pop together. In short, the instrumental virtuosity and expansive structures found in the former are combined with the catchiness, oftentimes simple melodies, and accessibility of the latter, to bring a sound distinct from both. To properly distinguish this genre, progressive pop is best viewed as a comparatively milder (or "pop") counterpart to progressive rock. Like in prog rock, the term "progressive" refers to the genre's attempts to break with standard music formulas. In the case of progressive pop, this means the standards of pop music prior to the mid to late 1960s, which was often short, simple, and had instrumentation that either involved guitar, bass and drum combos or traditional orchestrated arrangements for vocalists. In contrast, progressive pop usually contains more eclectic (sometimes quasi-symphonic) instrumentation, song times longer than the average 2.5 minutes, unorthodox harmonic structures (for pop), and/or abnormal timbres and textures.