With the advent of YouTube, we now have access to a lot of isolated instrumental tracks for classic tunes which allow the listener to more clearly hear and appreciate the musicianship and see how the layers of a recording are produced.
This is Eric Clapton's guitar solo on The Beatles While My Guitar Gently Weeps, one of the most popular cuts from The White Album (1968). The song is a George Harrison composition and according to George none of the other Beatles showed much interest during its recording. Harrison was dissatisfied with his own attempts at a guitar solo and asked his friend, Clapton, to come and take a shot at the solo which became the version we're all familiar with. (Via Open Culture)
This is what George, Paul and John sound like as solo guitarists. It's from The End (Abbey Road 1969) when all three take turns soloing. This clip tells you who is playing when.
And finally, here is George Harrison's lovely demo for While My Guitar Gently Weeps. You'll notice two things. First, the last verse of the demo version does not appear in the final recording and second, George Martin overdubbed strings on the demo as part of the production of the Love album, released in 2006.