Depending on one's attitude toward popular fiction, William F. Jenkins might well be regarded as either the quintessential hack or the epitome of the highly professional fiction writer. Of more than one thousand short stories and nearly seventy novels that he wrote during his long career, relatively little stand out as remarkable from today's perspective, but even fewer seem incompetent or poorly crafted. Though he wrote westerns, adventure tales, murder mysteries, and fiction for magazines such as the Saturday Evening Post and Collier's, Jenkins's reputation rests mainly on the huge body of science fiction he produced under the name Murray Leinster (though occasionally he would use Will F. Jenkins for the slick magazines or William Fitzgerald in issues of science-fiction magazines that already contained one Murray Leinster story, offering some hint of his prolificness). The Leinster canon is worth studying, if for no other reason, simply because...