Across the spectrum of literary and cinematic genres, science fiction has long since proved one of the most enduring and popular of them all. This is no doubt largely down to its tremendous malleability.
Hard science fiction (SF as opposed to 'sci-fi') has a rich history in its own right, historically with a fairly select audience; and yet, most readers, and certainly most film lovers are bound to have at least a few favourites that in some way qualify as science fiction, even if the reader/viewer in question doesn't necessarily regard themselves a genre fan.
For proof of this, we need look no further than the ongoing popularity of Star Wars, or the fact that the biggest box office hit of all time remains the otherworldly adventure Avatar. Terminator, Transformers, the Marvel Cinematic Universe: all these powerhouse franchises can quite reasonably be classed as science fiction.
Still, it's not all major blockbusters, or such critically praised genre entries as Stanley Kubrick's 2001: A Space Odyssey, Ridley Scott's Blade Runner, or - more recently - Denis Villeneuve's Arrival and Blade Runner 2049. There are plenty more great science fiction films that don't necessarily get held up in such high regard.
Here are 10 such science fiction films that perhaps don't get the love they deserve. Reflecting the breadth of the genre, they range from the highly intellectual to the patently absurd; indeed, in some cases they're a potent mix of the two. But all are well worth seeing if you've missed them so far.
10. Pi (π)
Years before he briefly revived Mickey Rourke's career with The Wrestler, steered Natalie Portman to Oscar glory with Black Swan, and freaked out just about everyone who saw mother!, US filmmaker Darren Aronofsky made his debut with this very unusual, ultra low-budget 1998 indie.
Pi's status as a science fiction film might be disputed by some, but then it's hard to narrow it down to any specific genre: it might be classed as a psychological thriller, there are clear horror overtones, and even hints of fantasy.
All in all, though, Pi deals with the potential of the human brain, the untapped regions within yet to be accessed - and the bizarre possibilities of such an endeavour. This surely qualifies as science fiction.
Sean Gullette (who also co-wrote the story with Aronofsky and Eric Watson) stars as Max, a genius mathematician working on a theory that numbers can explain everything in nature. Attempting to make stock market predictions via the mathematical constant pi, Max's computer churns out a seemingly random number which turns out to have very significant ramifications.
Max soon finds himself being followed by mysterious strangers, with all manner of sinister forces amassing around him in order to capitalise on his 'discovery'... or is it all just a paranoid delusion?
It sounds confusing as hell, and - well - it is. But you don't need to understand the mathematics to be captivated by the incredibly tense, oppressive, mind-bending atmosphere the film generates.