Council for the Literature of the Fantastic  
   A very scholarly approach to fantastic literature.
   http://www.uri.edu/artsci/english/clf/index.html

Definitions of Science Fiction  
   More than fifty definitions of science fiction from authors.
   http://www.panix.com/~gokce/sf_defn.html

Science Fiction Research Bibliography  
   An extensive bibliography of printed reference material related to science fiction deemed valueable for research into the subject, from books available at Washington State University's Holland Library.
   http://www.wsu.edu:8080/~brians/science_fiction/sfresearch.html

Science Fiction Studies  
   Website contains all article-abstracts and full texts of all reviews published in the journal since its founding in 1973, as well as featured essays, documents in the history of sf, and a bibliography of sf-criticism.
   http://www.uiowa.edu/~sfs

Kittywompus Tracks Fanzines  
   A weblog providing critical reviews of paper and electronic SF fanzines.
   http://www.kittywompus.com/fanzines/reviews

Tonya's Sphere of Influence  
   A brief historical survey of women writers of science fiction.
   http://www.cwrl.utexas.edu/~tonya/Tonya/sf/history.html

Her World Exploded  
   Essay taking the view that science fiction is about how you read a story, not how it's written.
   http://public.logica.com/~stepneys/sf/explode.htm

Kay Fowler  
   Essay about themes and genres. Lists lots of examples.
   http://orion.ramapo.edu/~kfowler/sfthemes.html

Some Observations on the New SF: An Essay  
   A thematic analysis of The Year's Best Science-Fiction, 1996-98.
   http://www.goodreports.net/newSF.htm

The Templeton Gate  
   Essays and reviews of Science Fiction authors, as well as SF films and television.
   http://members.tripod.com/templetongate

Science Fiction and Society  
   Discusses science fiction and its ties to human culture and social issues. Features new articles weekly, discussions, polls, and links.
   http://www.suite101.com/welcome.cfm/sf_and_society

Classics of Science Fiction  
   Identifying the classic books of science fiction.
   http://classics.jameswallaceharris.com/

Quantum Cosmos  
   Bibliography, essays and literary writings by Douglas A. Mackey, as well as reviews of books on physics and consciousness.
   http://www.quantumcosmos.com/

scifi/Hack1  
   For users learning how to write or critique science fiction.
   http://www.geocities.com/scifihack1/index.html