In 1943, he joined the Navy's highly secret radar corps.

In truth, they only visit Chaulssin to hold highly secret meetings.

Both employ highly secret technology to elude air defense systems.

I did manage to extract information on a highly secret project that may be related.

The system was highly secret as surprise was considered essential to its use.

The Athletics, whose offer has been kept highly secret, are seen as the leading contender.

Both plans were highly secret at the time of their creation and it was not until 1998 that they were made public.

The full extent of the American role is considered highly secret.

This was a highly secret and at the same time a very heavily advertised meeting.

Were they checking him out to see whether he could be trusted with a highly secret psi technology?