First published in 1979. What do we mean by Science Fiction? What does it do, and why do so many people read it? What are its characteristic values, attitudes and procedures? Is it a creative force in our society, or merely a pathological symptom? How much of it is worth the attention of the ordinary 'non-scientific' or 'non-addicted' reader? That these questions are frequently asked is a consequence of Science Fiction's current status as a highly popular and fashionable art-form. They are not easy to answer because SF is a confused concept and a confused field, varying from formula-repetition and institutionalized self-congratulation on the one hand to the most profound imaginative achievements on the other. This Critical Guide attempts a composite portrait of science fiction as a form of creative literature: not, that is, as a disembodied current of notions and ideas (e.g. about technological progress), nor as a 'sub-literature' which may only one day hope to aspire to literary status.