29,674

Walmsley group arrives at Galactic Center in Watcher craft.

29,683

First human entry into Wedge. Some communication with Old Ones.

29,721

Arrival of Earth fleet expedition at Galactic Center.

29,724

Meeting of Earth expedition and Walmsley group.

30,000-34,547

The “Great Times” of human development. Unsuccessful search for Galactic Library. Successive conflicts with mechanicals. Development of higher layers of mechanical “sheet intelligences.” Philosophical conflicts within mechanical civilizations. Formation of mechanical artistic philosophy.

34,547-35,792

Chandelier Age. Humans protect themselves against rising mechanical incursions. Participation

of earlier humans from the Walmsley expedition. Some collaboration with Cyber organic/mechanical forms. Discovery of Galactic Library in the Wedge.

35,792-37,463

The “Hunker Down.” Exodus from the Chandeliers to many planets within 80 light-years of Absolute Center. Includes High Arcology Era, Late Arcology Era, and High Citadel Age as human societies contract under Darwinnowing effects of mechanical competition.

37,498

Fall of Family Bishop Citadel on Snowglade, termed the “Calamity.”

37,504

Escape of Family Bishop from Snowglade in ancient human vessel. Clandestine oversight of this band by Mantis level mechanicals.

37,509

Surviving Bishops reach nearest star, encounter Cybers. Defeat local mechanicals. Adopt some human refugees.

37,510

Bishops reach Absolute Center, center Wedge.

37,518

Temporal sequences become stochastically ordered. Release of Trigger Codes into mechanical minds. Death of most mechanical forms. Intervention of Highers to rectify damage done by excessive mechanical expansion.

* * *

Preservation of several human varieties. Archiving of early forms in several deeply embedded representations.

Beginning of cooperation between Higher mechanically-based forms and organic (“Natural”) forms. Decision to address the larger problems of all lifeforms by Syntony, in collaboration with aspects of lower forms.

Beginning of mature phase of self-organized forms.

END OF PREAMBLE.

LATER EVENTS CANNOT BE

THUS REPRESENTED.

About the Author

GREGORY BENFORD is a professor of physics at the University of California, Irvine. He is a Woodrow Wilson Fellow, was a Visiting Fellow at Cambridge University, and in 1995 received the Lord Prize for contributions to science. His research encompasses both theory and experiments in the fields of astrophysics and plasma physics. His fiction has won many awards, including two Nebula Awards, one John W. Campbell Award, and one British SF Award. Dr. Benford makes his home in Laguna Beach, California.

Gregory Benford is an eminent physicist, multiple award-winning author, and recipient of the United Nations Prize for Literature. Now in a new, revised edition, here is the continuing story of his classic Galactic Center series, a triumph of breathtaking imagination and tense human drama set against an immeasurable tapestry of space, time, and evolution.

GREAT SKY RIVER

Nearly 100,000 years after first contact with the machines that dominate the universe, only a few hundred humans survive. Trapped on Snowglade, a barren world near the center of the galaxy, Killeen and his child Toby of the Bishop Tribe are primitive scavengers, homeless and hunted by the ruling “mechs.” Then suddenly, a strange cosmic entity—neither organic nor cybernetic nor living matter—reaches out from a black hole to speak with Killeen. But can the fallen descendant of starfarers understand this alien being in time—and seize his only chance to save his family and mankind from final annihilation?

“Overwhelming power…irresistible strength.”

—WASHINGTON POST BOOK WORLD

“Hard science fiction at its very best.”

—ST. LOUIS POST-DISPATCH

DON’T MISS BOOK 4 OF THE GALACTIC CENTER SERIES, TIDES OF LIGHT