Henry Kissinger under President Nixon and John Foster Dulles under President Eisenhower were modern titans.

BBC: Hillary Clinton: A year in the shadow of Barack Obama

Both Nixon and Kissinger are like two kids caught doing something naughty, cajoling and squabbling as they try to both get off the hook, either together or at the expense of the other.

BBC: Nixon's final hours

Thomas Friedman, a New York Times columnist, argues that, if they want to have a successful foreign policy, presidents need to have a close personal bond with their secretaries of state: witness Richard Nixon and Henry Kissinger or George Bush senior and James Baker.

ECONOMIST: Lexington

His duties at the White House, on Henry Kissinger's National Security Council and for Nixon, had been carried out while still under military orders and earned him a dizzy ascent, from colonel to four-star general in four years.

ECONOMIST: Alexander Haig

But who studies the works of Christian Archibald Herter, also a secretary of state under Eisenhower, and William P Rogers, who preceded Kissinger under Nixon?

BBC: Hillary Clinton: A year in the shadow of Barack Obama