Hearing of the death of Phil Ramone (I suppose he deserves his own thread) got me thinking about legendary engineer/mixer/producer Shelly Yakus for some reason, which got me thinking about John Lennon's 1973 Mind Games album, which was engineered by Yakus.
Mind Games is my favorite Lennon album, and I can't think of the album without thinking of one of my favorite cuts on it, "Aisumasen (I'm Sorry)" and the killer guitar solo which concludes the song. The solo is by David Spinozza, a top New York session musician who has the distinction of being one of the very few non-Beatles to have played on albums by both John Lennon and Paul McCartney (he also played on McCartney's Ram). "Aisumasen" is a beautiful and powerful song already, but Spinozza's extended solo brings it home in a moving fashion that is both plaintive and hopeful, and is so remarkable that Lennon uncharacteristically chose to close the song with about 45 seconds of guitar solo with no vocal at all.
The next solo comes from the aforementioned Ram by Paul and Linda McCartney. But although he appears on this album, too, this one is not Spinozza, but another crack session ace, Hugh McCracken on the song "Too Many People." On an album dismissed by most fans and critics but a sentimental favorite of mine because of the memories of discovering and exploring it when it came out, "Too Many People" is to my mind the best tune, and was second only to "Uncle Albert/Admiral Halsey" in popularity and chart success. It is a promising start to the album, which has a lot of good stuff on it, and it is certainly much better and more polished than his previous McCartney, it still succumbs to the clichés and twee-ness that most of his solo work without the cold, stern criticism of Lennon suffers from. Without Lennon to compete with within the Beatles, McCartney wasn't driven to always present his best work, but rather whatever would suffice.
Those are my two favorite uncredited solos from Lennon and McCartney.
If that's not enough to get any discussion going, how about these:
Probably everyone knows the solo in "While My Guitar Gently Weeps" was by Eric Clapton, but did you know that the guitar solos in "Taxman" and "Good Morning, Good Morning" were by Paul McCartney, not George Harrison? I listened to those songs for many years before I knew that. As I understand it from various sources, in both cases it was a matter of Paul's impatience with waiting for George to come up with an adequate solo, as George tended to take a long time composing and perfecting his solos, and was never good at improvisation. On the one hand, it reinforces the lack of respect with which Paul often treated George which really bothers me, but on the other hand, they are both outstanding, dynamite solos and it's hard to condemn Paul for giving them to the world.