Emerson is the man. Have you seen his improv videos on youtube? Amazing.
I love the final movement of his piano concerto. I also really like his piano piece called "Lachesis".ELP is my favorite prog band of the 70s. I saw them live in concert in 1992, i was too young¡¡¡. Great show.
Emerson never had a lesson in his entire life if I am not entirely wrong.
I am quite sure you are wrong. To quote from wikipedia(I have read the same thing many oter places): As a child, he learned western classical music, from which he derived a lot of inspiration to create his own style, combining classical music, jazz, and rock themes.