The six great lookout plates into which the alert observers peered were blank, their far-flung ultra-sensitive detector screens encountering no obstacle-the ether was empty for thousands upon thousands of kilometers.

Topper was an alert observer of the scene, as was wise for an ambitious young officer whose superior could be cryptic.

However, for the quiet, alert observer, one of the treats that Big Morongo offers is the prospect of encountering a bobcat, especially at dusk or dawn.

If there were alert observers in the building, then the Terrans, standing out in the full light of the 2 moons, had just been seen.

But the Sorceress's pale eyes were sharp, as alert as those of the furtive Jipol observers who were so obvious to her in the crowd.

Unseen but acutely felt, alert observers watched her from the hooded cowls of those pines, creatures less ordinary than owls and raccoons, and less clean.

Many of the buildings from the camp still stand, used as farm buildings throughout central Utah, and an alert observer will see several of them during the drive to and from the central area site.

Its nullifiers were full on, every blocking screen was out, every plate upon every ship was hot and was being scanned by alert and keen-eyed observers.

The story is narrated by Marnus, the youngest child and only son, who is an alert and vigilant but innocent observer.

If there were any alert observers on Siliko 5 they must have the impression by now that the small spacecraft had damaged its guidance controls.