Hollister describes Miles' marriage to Sibyl as having been a "crucial breakthrough in his career".

Scientists studying malaria believe they may have made a crucial breakthrough which could lead to the development of an effective vaccine against the disease.

They believe a Government promise to waive the clause could be the crucial breakthrough.

"This is a crucial breakthrough," a senior Croatian official said of the discussions, which lasted four and a half hours.

Others are recognized as crucial breakthroughs in the art of their time.

We've split the atom," on the day of the crucial breakthrough, the anecdote is almost certainly apocryphal.

And David realized this was something of a crucial breakthrough.

If these approaches lead to successful talks with important elements of the insurgency, it would be a crucial breakthrough.

The crucial breakthrough was the idea of combining fuel, structure, containment, and neutron moderator in a small, strong sphere.

The armored divisions must be used for the crucial breakthrough.