Notes
Across a Billion Years, a standalone juvenile novel by Robert Silverberg.

The image opposite and the blurb below are from the 1979 Magnum Books paperback edition, ISBN 0417031505. Cover illustration by Peter Elson.

Publisher's Blurb – Lower Cover
Excavating on the planet Highby V in the search for the remains of a mysterious civilization, the members of a twenty-fourth century archaeological expedition are plunged into a fantastic interplanetary search for its creators. For the 'High Ones' from the past have left extraordinary evidence of their civilization in the form of films of their daily life. Highly intelligent beings, they built glorious cities and travelled in space at a time when dinosaurs roamed the earth.

The researchers race from planet to planet, convinced that somewhere in the galaxy there are still High Ones alive. But what they finally find is stranger – and more exciting – than anything they could possibly have imagined.