Aboard the spacecraft Leonora Christine, fifty crewmembers, half men and half women, have embarked on a journey of discovery like no other to a planet thirty light-years away. Experienced scientists and researchers, they have come to terms with the time conditions of their space travel. To survive, the crewmembers have no choice but to bypass their destination and continue to accelerate toward the speed of light. But how will they keep hope alive and maintain order as they hurtle deeper into space with time passing more and more rapidly, and their ultimate fate unknown? With its combination of mind-blowing hard science and compelling human drama, Tau Zero is "the ultimate hard science novel" (Mike Resnick).