The books have been reprinted a number of times as a trilogy (as well as many times separately): in 1986 by Ballantine Books as "Galactic Empire Novel[s]", in 1992 by Spectra as "The Empire Novels" and in 2010 along with The End of Eternity by Orb Books, in both print and Kindle editions.
The books have been reprinted a number of times as a trilogy (as well as many times separately): in 1986 by Ballantine Books as "Galactic Empire Novel[s]", in 1992 by Spectra as "The Empire Novels" and in 2010 along with The End of Eternity by Orb Books in both print and Kindle editions.