--It must have literary value
--It must meet the needs of the students
--Intellectual cohesion and scientific plausibility. In sciece fiction the author can make up the rules but the author has to follow them. There are no limits to what can happen in the world. The author should use a genuine hypothisis of a projected future or a convincing fake(LeGuin,22). It needs to follow the rules of nature, and science. It needs to seem possible.
--A movement from the old to the new first contact, change, alternatives, and estrangements are possibilities.
--Has stood the test of time.
--There is no slang. Slang tends to go out of style and can date a text.
--The text discusses issues that are relavant today