A crucial dynamic in the writing of speculative fiction is the tension between Fantasy and Science Fiction. Of course, for some the distinction between these two terms is very clear: Fantasy, like Tolkien, includes magic; SF, like Arthur C. Clarke, technology. But Clarke famously noted that any sufficiently advanced technology will appear magical; and the best examples of the genre demonstrate that the borderline between these two things is far from clear. Zelazny's Lord of Light is a brilliant demonstration of this: a novel at one and the same time both a superb science fictional tale, in which all the fabulous and fantastical things that happen are rationalized in technological terms; and a superb example of High Fantasy, in which gods and demons mingle with mortals and powerful magic is loosed upon the world. Indeed, one way of reading Lord of Light is as a modification of Clarke's celebrated apothegm: any sufficiently advanced technology, Zelazny is saying, is indistinguishable from religious myth.
Adam Roberts, na introdução de Lord of Light, de Roger Zelazny (1967), edição SF Masterworks da Gollancz.