As The Hunger Games: Mockingjay - Part 1 opens in Singapore tomorrow, some might remember a time when young-adult fiction and movies made from the novels were just called "novels" and "movies".
If a genre needed to be given, the film might be dismissively tagged as "teen" fare or, if it was more posh (or European), blessed with the term "coming-of-age film".
But the astounding success of the Twilight series sent tremors through Hollywood and, in its wake, the Young Adult, or YA, template was created.
The studio accountants loved it, but for many others - including film fans - it was yet another sign of Tinseltown's creative bankruptcy.
To understand why YA movies are the genre du jour (in the same way that Star Wars, Jaws and Indiana Jones created genres and started a flood of me-too works), it helps to understand how financially conservative Hollywood has become in recent years.
With fewer and fewer people turning up in movie theatres in America, films these days are greenlit on factors such as built-in marketing (is it based on a best-selling property?) and foreign market appeal (will people in China understand the story?).
Properties like that do not come along every day, so this is why films based on the Marvel Universe are now huge. But they are expensive to make - they tend to feature top-earning actors (Robert Downey Jr as Iron Man, for example).
Mistakes are costly, so expensive branding exercises are the norm - witness the all-out campaign to raise awareness for this year's big hit, Guardians Of The Galaxy, which saw the cast touring key Asian cites, including Singapore, earlier this year.
Enter the young-adult novel. It has a few defining characteristics: a teen protagonist (often female), a romance fraught with difficult choices, with a finale that sees her coming to terms with herself and winning love and respect all around.
Movies made from these books have all the safety factors that make studio heads happy, with the bonus that they do not require expensive star casts. Like the horror genre, they are relatively cheap to make and, also like splatter or spook films that break out into the mainstream, break-out YA films can be extremely lucrative.
But what seems to be everywhere now is the subgenre of YA science-fiction and fantasy. Because there is simply more stuff going on - vampires, werewolves, explosions, chases, missions - it ups the chances that it will draw patrons who do not give a hoot about the book or its characters.
Franchisability, scale and spectacle are what separate a niche YA movie (The Princess Diaries, 2001-2004; The Perks Of Being A Wallflower, 2012) from big-budget projects such as The Hunger Games (from 2012), Divergent (2014), The Maze Runner (2014), The Mortal Instruments (2013) and The Twilight series (2008-2012).