The rise in national industry concentration in the US between 1977 and 2013 is driven by a new industrial revolution in three broad non-traded sectors: services, retail, and wholesale. Sectors where national concentration is rising have increased their share of employment, and the expansion is...

Orson Wells made Citizen Kane, his greatest movie, when he was 25 years old; Frank Lloyd Wright designed Fallingwater, his most famous house, when he was 70. Contrasts as great as this raise the question of whether there is a general explanation of when in their lives great innovators are most...