Sorry, but you're probably going to be pretty hard pressed to find something under 200 pages in the sci-fi department that doesn't qualify as complete crap (see "Animorphs", as much as I did like that series when I was a kid...) What I can do though is give you some interesting sci-fi that is decently written and should be interesting from whatever walk of life you're from.
Also, are you allowed to do fantasy? Or just science fiction?
Either way, there are my suggestions for both:
For fantasy, try something like David Eddings' Redemption of Althalus. No hoity, toity complicated magical stuff here and the characters are witty and adorable in their own way. Anything by Eddings is good for this if you can find a shorter one, but I would suggest this one as it is a stand alone book.
Also, Piers Anthony is a pretty good fantasy sci-fi/fantasy writer and very accessible. I'd suggest the "Incarnations of Immortality" series if you want something "not too weird".
In terms of pure sci-fi, as you may have guessed, the majority is probably a bit...geeky/weird. Even the more popular ones for me are a bit odd (Vonnegut and Asimov included....). Still, there are a few out there that are more fun than complicated. A few years back I read a book called Masque by F. Paul Wilson, pretty easy read and the story was pretty entertaining.
If you can push it and you REALLY want something short, an alternative you may not have thought of is a graphic novel. Or, as the less pretentious of us like to call it: a comic book. Superheros undoubtedly fall into the category of science fiction. I would suggest Marvel over DC just because it tends to be more accessible and less dark. So, in that genre, I would say pretty much anything with Spider-Man or Fantastic Four would be your best bet for something more gender neutral.
Overall though, sci-fi is what it is, but give whatever you read a fair chance. I've personally read every one of those books (with the exception of the graphic novels...there's no way I could get through all of them) and I can personally tell you that they're all fun and pretty easy to read.
Plus, even though I am a bit of a geek myself, without good characters and a good story, any book is boring so don't think I'm just recommending these because I like sci-fi. :P
Just don't knock it until you try it is all I'm saying.
· 1 decade ago