Remember the CD-ROM reference software of the late eighties and early nineties - titles like Microsoft Encarta? My favourite title was probably Cinemania, a delightful reference work that included articles on practically every movie ever made, complete with reviews by Ebert, Maltin and Kael as well as multimedia features like photos, audio files and movie clips. Cinemania featured a gorgeous, easy to use interface and its depth and breadth of coverage was unrivalled. I was such a fan that I even wrote Microsoft with a list of suggested improvements, including a whole new product, TVMania.
Of course the World Wide Web made Encarta, Cinemania and a host of other CD-ROM titles obsolete, including another of my favourites, the Encyclopedia of Science Fiction, an exhaustive reference work covering all aspects of SF. Well, good news! The original authors have put the SFE on the web, with even more material. The encyclopedia is now over three million words long, with another million or so words to come over the course of the next year.
Coverage is extremely broad, the analysis brief but insightful. John Clute's editorial opinion is easy to spot in many articles and readers may find themselves disagreeing with his point of view from time to time, but overall I think he's fair. There's plenty of history to enjoy here, but the chief value of this work, for me at least, is its tendency to add many authors and titles to your reading list.
I encourage fans of SF to visit the Science Fiction Encyclopedia here.