Though this is a brief book Card covers interesting ground. I'm a sci-fi neophyte myself, but I have read a lot of fantasy, especially the non-epic, YA variety. If you're familiar with these genres a lot of what Card has to say you will know implicitly. For example, "the rules" of magic in stories: there must be some cost to the user; power can't be limitless. Because I don't know much about sci-fi I found many passages of this book very helpful--and Card spends most of his time discussing sci-fi rather than fantasy. For example, the rules of starflight. Chances are that if you are writing a sci-fi you're going to have your characters in space at some point, or they will have just landed, or someone will be arriving from far away etc. I don't know where else you'd be able to find a discussion of the various types of imaginary space travel and how they will affect story, but it's here in Card's book and worth buying the book for this alone. One thing that he stresses over and over again is that you're writing science fiction: the science must make sense even if it's physically impossible, at this point in time or any. He writes one particularly amusing passage about warp speed:
I haven't even touched on the silliest of space travel rules--the one used in the Star Trek universe, where the speed of light is no more a barrier than the speed of sound, and you only have to persuade Scotty in the engine room to really step on the gas to get four, eight, ten times the speed of light. This sort of stardrive shows such contempt for science that it's best to reserve it for light adventures or comic stories--or, of course, Star Trek novelisations ... Beware of anything that makes non-Trekkie readers think of Star Trek.
I'm glad someone told me this before I had one of my characters shouting, "Increase to warp speed ten!"
Card also covers made up words and languages and how to use them, the problem with metaphor in science fiction, and how quickly you can lose a reader by being sloppy. Because it's just so interesting, let me explain to you what he said about those last two.
The problem with metaphor in sf&f is your reader will probably take you literally. If you write, "She approached the door with leaden feet," a reader might assume the character's feet are made of lead. Card also has this to say about being sloppy and faking it:
Wherever you can be truthful, you should be truthful; if your readers can see that you're acting by a credo, they'll trust you, and you'll deserve their trust. But if they catch you faking it, and doing it so carelessly that you can easily be caught, they'll figure that if the story wasn't worth much effort to you, it shouldn't be much worth to them, either.
I'll go one step further with this: if your careless, you're reader will assume that you think he or she is stupid. Nothing enrages me more than action films that blatantly disobey the laws of physics: the nuclear blast that Indiana Jones survives by hiding in a refrigerator; James Bond falling over a cliff after his light plane and then catching up to it as they falls; in fact, just about everything in the James Bond universe. (Except Casino Royale. Casino Royale was brilliant and funny, and then that damn Russian (Russian?) biatch had to go and break his heart and we're back to wooden, Mr too-many-car-chases Bond. P.S. Daniel Craig=swoonarama.)
There's lots of insightful nuggets in this book. It's not a book on writing that you would read for pleasure as well, like Bird by Bird, but it's pithy and useful, as all good how-to books should be.
*scampers off to perve on Daniel Craig in those blue swimming trunks*