The following is a list of the 20 best American science fiction authors in the field today (that are still writing today).  Of course, this list is strictly my opinion and I know I will get agreements along with disagreements with my selections.  With any list that is created there will be some items, authors in this case, that will get left out but I truly believe that I have captured at least some of the best authors if not all of them in this list.  I have tried to give these authors a fair appraisal in some of the following criteria: number of books written, number of awards won, and overall popularity of books.  Below is the list of the best American science fiction authors along with some of their more popular novels or books.  The list is in no particular order. 

1. Ray Bradbury  –  Fahrenheit 451, Martian Chronicles, Bradbury Stories.
2. Larry Niven  –  Ringworld, Mote in God’s Eye, Destiny’s Road.
3. Lois McMaster Bujold  –  Barrayar, Mirror Dance, The Vor Game.
4. Ben Bova  –  Saturn, Jupiter, Return to Mars.
5. Jack McDevitt  –  Engines of God, Polaris, Ancient Shores.
6. Gregory Benford  –  Furious Gulf, Timescape, Eater.
7. Anne McCaffrey  –  The Chronicles of Pern, Dragonsdawn, Dragon’s Fire.
8. Elizabeth Moon  –  Sheepfarmer’s Daughter, Once a Hero, Marque and Reprisal.
9. Ursula Le Guin  –  All Earthsea Books, The Lathe of Heaven, Fisherman of Inland Sea.
10. Frederick Pohl  –  Gateway, Man Plus, Jem.
11. Connie Willis  –  Doomsday Book, To Say Nothing of the Dog, Passage.
12. David Brin  –  Startide Rising, The Uplift War, Brightness Reef.
13. Sheri Tepper  –  The Fresco, A Plague of Angels, Grass.
14. Greg Bear  –  Darwin’s Radio, The Forge of God, Queen of Angels.
15. Kim Stanley Robinson  –  Green, Blue and Green Mars Trilogy, The Martians, Antarctica.
16. Robert Silverburg  –  Time of Changes, Dying Inside, The Alien Years.
17. Orson Scott Card  –  Ender’s Game, Maps in a Mirror, Speaker for the Dead.
18. Mike Resnick  –  Entire Starship Series, Purgatory, Return of Santiago.
19. Dan Simmons  –  Hyperion, The Crook Factory, The Rise of Endymion.
20. Joe Haldeman  –  The Forever War, Forever Peace, Camouflage.

Some Honorable Mention American Authors:

• Gene Wolfe
• Allan Steele
• Alan Dean Foster
• John Varley
• James Gunn
• CJ Cherryh  (just missed the list #21 for sure)
• Spider Robinson
• Charles Pelligrino
• Joan Vinge
• James Morrow

Well, that completes my list for the best American science fiction authors still writing today.  Be sure to check out my next article with the best foreign authors in science fiction that I will be publishing shortly.  Please feel free to comment if you agree with the list.  And if you think I excluded someone then please comment on that too.   I would love to hear some feedback on who other people consider the best authors to be.