It's widely agreed that The Beatles were the most influential, and to many, simply the best, rock band of all time. However, what tends to be overlooked is the fact that they were also one of the most daring rock bands, especially when you realize how much they changed both musically and visually from 1964 through 1970. Also, how they started out as a pop band, and ended up taking on a variety of styles and utilizing an increasing amount of experimentation.
In the 2020 book, "John Winston Ono Lennon," Beatles expert Brian Kehew, who was the co-author of the exhaustive "Recording The Beatles" book, discussed the member of the band who was undoubtedly the most daring when it came to experimental music, John Lennon, and when and how he came to embrace that side of his artistry.
"The experimentalism is a thread that has certainly been around for a few decades in the underground," Kehew said. "And those were not pop-y records. I don't know if he expected lots of people to buy 'Life with the Lions,' as much as he just wanted to do it. And in a way – because he was such an aggressive, pushy, 'I know what's good' person – he put it out, expecting people would listen to it and maybe be offended...like how an album cover offends people. They knew how to do that, too."
Source: Ultimate Guitar