Constant physics in an evolving universe -- As the universe expands -- What is antimatter? -- Enter neutrinos -- Mesons -- Through the looking glass -- Through the looking antiglass -- The survival of matter -- Enter quarks -- Energy rules -- Symmetry rules -- Standard model gauge symmetries -- A missing piece -- It still doesn't work! -- Tools of the trade -- Searching for clues -- Speculations -- Neutrino surprises -- Following the new clue.