The crucial instruments involved in their plan are a special map and the Foucault pendulum.

Weapons were not the only crucial instruments for a knight.

I consider radio to be the most modern and the most crucial instrument for influencing the masses.

The printing press was the crucial instrument in this process.

For the moment, though, one crucial instrument of economic policy is not in the Government's hands.

It refused to use its technology to jam radio broadcasts that were a crucial instrument in the coordination and perpetuation of the genocide.

It needs to become a crucial instrument of the European Union's policy.

In this the European Neighbourhood Policy is a crucial instrument.

This is undoubtedly a crucial instrument that is going to mark all of our policies over the next decade.

But the performer's imagination is as crucial an instrument.