| U.S.S by Jodi Dulecki - 2011 |
| Uhura's Song by Janet Kagan - 2000 - 384 pages |
| Uller Uprising by H. Beam Piper - 2007 - 136 pages |
| Ultimate Warning by Peter A. Legault - 2012 - 328 pages |
| Uluru Rising by Jeff Todd - 2011 |
| Un Lun Dun by China Mieville - 2008 - 474 pages |
| Un Lun Dun by China Mieville - 2008 - 474 pages |
| Uncharted by Christopher Golden - 2011 - 322 pages |
| Uncharted Territory by Connie Willis - 2009 - 160 pages |
| Uncharted Territory by Connie Willis - 1994 - 160 pages |
| Uncharted Territory by Connie Willis - 1994 - 160 pages |
| Uncharted: The Fourth Labyrinth by Christopher Golden - 2011 - 336 pages |
| Unchecked Time by Richard Cohen - 2002 |
| Unchosen Destiny by Kathie Lightfoot - 2012 |
| Under the Sun by John Mear - 2004 |
| Underwater Space Aliens by Michael Joseph - 2009 - 312 pages |
| Unexpected Heroes by Charlene Haines - 2008 - 176 pages |
| Unholy Birth by Andrew Neiderman - 2007 - 352 pages |
| United Star Systems Marines by Hunter Opilla - 2011 |
| Unity by S.D. Perry - 2003 - 336 pages |
| Unity Above All by L. Gilbert - 2011 - 274 pages |
| Universal Conflict by David Claridge - 2012 - 312 pages |
| Universe of the Soul by Jennifer Mandelas - 2011 |
| Unnatural Selection by Philip Eastwood - 2010 |
| Unraveling Time by Kurt R. A. Giambastiani - 2006 - 264 pages |
| Until the Stars Grow Cold by Terence West - 2006 |
| Unwise Child by Randall Garrett - 2010 - 214 pages |
| Unwise Child by Randall Garrett - 2008 - 188 pages |
| Unwise Child by Randall Garrett - 2008 - 168 pages |
| Unwise Child by Randall Garrett - 2008 - 188 pages |
| Unwise Child by Randall Garrett - 2008 - 188 pages |
| Urgency by Paul R. Smith - 2006 - 334 pages |
| Use of Weapons by Iain M. Banks - 2008 - 499 pages |
| Use of weapons by Iain Banks - 1990 - 389 pages |
| Useful Humans by Rich La Bonte - 2005 - 376 pages |
| Usher's Harbour by Barry Epstein, Darls Epstein - 2012 |
| Utopia by Lincoln Child - 2003 - 514 pages |
| Utopia by Lincoln Child - 2002 - 385 pages |
| Utopia X by Professor Scott Wilson - 2004 - 264 pages |
| Utopia X by Professor Scott Wilson, Wilson - 2004 |