On a sunny morning in the streets of Havana, Cuba, May 17, 1977, I clambered down the gangplank of the M.T.S. Daphne cruise ship, carrying all my instruments. Dizzy Gillespie was already on shore, the first one of us to leave the ship, surrounded by adoring fans and acting as a one-man State Department representative of the best that America has to offer the world.