As Barack Obama, the Democratic presidential candidate, quietly prepares for Denver, the focus at the convention will be on drama and psychodrama. The drama comes from doubts about whether Mr Obama can give the speech of his life; the psychodrama from the Clintons, who have muscled their way into two prime-time speaking slots.

Dynastic strife and do-or-die live performances are hard to beat. But the assembled officials should also turn their attention to the academic universe of charts, equations and carefully honed arguments in Claudia Goldin and Lawrence Katz's fine new book, The Race Between Technology and Education . Goldin and Katz, both professors of economics at Harvard, tackle the most important US economic trend, and, hence, most critical domestic issue - growing income inequality.