Fred Cassidy, thirteen years an undergraduate and an acrophiliac, joins Professor Paul Byler in a search for their laboratory replica of an alien artifact of interest to more than one interstellar community

La pierre des étoiles is a translation of this work.

Stersteen is a translation of this work.

Tore in der Wüste is a translation of this work.

Bramy w piasku is a translation of this work.

Le rocce dell'impero is a translation of this work.