Speculative fiction is easily fragmented by both readers and the industry, and even the professionals are capable of causing enormous rifts between major wings: look no further than the mid-nineties’ hilariously unnecessary epic saga of the SFWA consideration for changing its acronym to SFFWA.

But the truth is simple: of the three major genres, Science Fiction was the first to market as a novel genre by the 1930s, even though fantasy’s roots in literature appear to extend much further back in time – at least as far as George MacDonald’s Phantastes in the 1850s. Horror, while recognizable in the Gothic romances of Frankenstein and Dracula, was the last to market as a recognizable section in the book store.

Put another way:

1. The SFWA was established in 1965.
2. The Horror Writers Association was not established until 1984.
3. Fantasy was officially added to the full name of the SFWA organization in 1992.

Considering that Anne McCaffrey was an editor of the SFWA bulletin in the 1960s, and that modern horror forefather Robert Bloch was also a leading member, it is safe to grant that Science Fiction truly is the catch-all that it is reputed to be, as much as it amuses me to meet young women who claim to be “into” science fiction, when what they mean is the Hunger Games and Harry Potter.

Yet, the distinctions are important. Just as the young lady above would likely recoil at Amazon recommending Foundation and Empire for her wish list, even the broadest fan of the genre is likely to generally gravitate towards one or the other.

So what binds them together? Is it merely a loose alliance of minority interests, a motley ghetto in a world of romance and mainstream fiction?

What unites the three major subdivisions of Science Fiction is Weird Fiction.

Just as fantasy grandmaster George R.R. Martin cut his writing teeth on such science fiction classics as The Sandkings, horror lord Stephen King ventured boldly into straight fantasy with The Eyes of the Dragon, and science fiction paragon Philip Jose Farmer (World of Tiers) is…well, okay, he’s just weird.

But that is sort of the point. If Asimov can be considered the furthest pole in the strict (i.e. “hard”) science fiction camp, then why did he find such a lucrative market in simply lending his name and editorial eye to so many (equally strict) fantasy anthologies?

H.P. Lovecraft is known for weird fiction, yet out of that fertile territory came the science fiction classic At the Mountains of Madness. Robert E. Howard was a Weird Tales regular for Solomon Kane stories, but what would modern fantasy be without Conan the Barbarian as an alternate stream to epic fantasy?

There is no Weird Fiction section in the book store. It is a sub-sub-sub category on Amazon. For contemporary novels, you might consider Mieville’s The City & The City or King and Straub’s The Talisman to be “weird fiction” but you will find it in the Science Fiction\Fantasy\Horror section.

Weird is the undefinable and infinite intersection of the three major genres. It is why Borges and Bradbury and Matheson and Heinlein can equally repel a mainstream reader while equally drawing the very same odd one.

It is also why too much division can be a harmful thing, why over-categorization can lead to alienation of readers who might otherwise enjoy a new twist on strange. Weird is a spiritual cord, and – while it may occasionally be useful to identify and distinguish a hand from a foot from a head – ultimately it is the entire body that acts, and excessive compartmentalization is nothing but the cold vivisection of a living thing.