Conversation so far:
What was special about the grateful dead?
The Dead's early sets centered around blues and R&B covers chosen by McKernan.
By the end of 1966.
what happened in 1966?
the end of 1966, Garcia had improved his musical skills and wanted to assert himself more as a leader and musical director.

Question: leader of what?
Self-contained rewrite: Garcia wanted to be a leader of what?