By the end of the second millennium, the human race has evolved into three distinct groups: conscious software programs known as citizens, sentient robots called gleisners and unaltered humans or fleshers.

When a cosmic accident forces the evacuation of Earth, these three groups form a tentative alliance to explore the known universe in search of unknown and perhaps unknowable possibilities.

Egan’s remarkable gift for infusing theoretical physics with vibrant immediacy, creating sympathetic characters that stretch the definition of humanity, results in an exhilarating galactic adventure that echoes the best efforts of Greg Bear, Larry Niven and other masters of hard SF.