"Science-fiction is a literary province I used to visit fairly often; if I now visit it seldom, that is not because my taste has improved but because the province has changed, being now covered with new building estates, in a style I don't care for. But in the good old days I noticed that whenever critics said anything about it, they betrayed great ignorance. They talked as if it were a homogeneous genre. But it is not, in the literary sense, a genre at all. There is nothing common to all who write it except the use of a particular 'machine'. Some of the writers are of the family of Jules Verne and are primarily interested in technology. Some use the machine simply for literary fantasy and produce what is essentially Märchen or myth. A great many use it for satire; nearly all the most pungent American criticism of the American way of life takes this form, and would at once be denounced as un-American if it ventured into any other. And finally, there is the great mass of hacks who merely 'cashed in' on the boom in science-fiction and used remote planets or even galaxies as the backcloth for spy-stories or love-stories which might as well or better have been located in Whitechapel or the Bronx. And as the stories differ in kind, so of course do their readers. You can, if you wish, class all science-fiction together; but it is about as perceptive as classing the works of Ballantyne, Conrad and W. W. Jacobs together as 'the sea-story' and then criticising that."