Excerpt from the introduction to The Rise and Rise of the Human Empire by Walter Fu Yin.

No one can really say what went before, but during the Last Rise of Civilisation one race stood above all the others. While many species' from many worlds all attained greatness, creating empires, federations and vast alliances, only the Humans could claim to be the most influential, most powerful and most knowledgeable of all of them.

The Humans rose from Earth into a galaxy where civilisation was in its infancy. Any Great Races that had come before had left or changed into something no longer recognisable to the upcoming worlds. The Humans spread quickly, driven by a sense of adventure and population pressures on their homeworld, expanding their influence to several star systems before they encountered another life-form. The Sand, as they became known, were a mineral-based life form unlike anything the Humans had encountered before. The two species were only able to communicate after a period of months and it was finally the Human diplomat, Senator Jammer Coves, who brokered the first Non-Aggression treaty between two alien species. Since the Sand were able to live without air, on barren worlds and inhospitable terrain (to Humans anyway) the two cultures were able to share worlds, goals, technology and influence. Though their points of view were rarely identical, the two species were able expand into their local area peacefully, safely and rapidly. It was a century before they first entered into armed conflict against each other, agitated by a third party, and it almost spelled the end of both cultures. Instead, it eventually led to the largest civilisation the Galaxy had ever seen.