Greetings, seekers of the good crack! Please bear with me, as I've never done a fandom overview before, but hopefully this one will serve. The Authority fandom is pretty small - it's not a hugely well-known comic - but like most tiny fandoms, what there is is of pretty kickass quality. As a source for fandom, it's got it all: mayhem, superpowers, complex morality, kickass female characters, a canonical gay couple, and a very cool spaceship.
The Authority is a Wildstorm comic, originally created by Warren Ellis using some characters he'd created for Stormwatch. The idea was that the Authority, led by Jenny Sparks, would do whatever it took to make a finer world - no matter how bone-crunchingly violent they had to be to get it done. This team had no problems with killing its bad guys: anything else would just put people back in danger.
The comic was notable for being one of the pioneers of decompression: huge, detailed splash panels, plots taking several issues to wrap up - you know, all that stuff that's so common nowadays that the opposite is novel again. It was also notable for how politics crept in after Ellis left the title: subsequent writers, like Mark Millar, made things more about The Authority vs. The World, which was not always recieved well. Flame wars still erupt on TV Tropes over the character interpretations. These days, however, the point's a little moot: the Wildstorm world has ended, spectacularly, and now the Authority are doing what they can to salvage the last remnants of humanity. A very intriguing apocalypse story with great characterisation has - for now at least - trumped all the political back-and-forth; it's a spectacular run that's well worth checking out.
But you're not here for the waffle! You're here so you can get to know the awesome people involved.
Jenny Sparks: Born in London on New Year's Day, 1900, Jenny Sparks is the Spirit of the 20th Century, the living zeitgeist. There's a Jenny every century (or thereabouts), stretching back to the dawn of humanity, and she's the latest; when we meet her, she's also a chain-smoking alcoholic and a very good-looking, but nonetheless weary, ninety-something. She forms the Authority because she's determined to make a real difference before she dies, and do what needs to be done without the red tape and politics that Stormwatch has to deal with. Or, in her own words: "Bugger this. I want a better world."
She finds The Carrier, a "shiftship" capable of traversing the Bleed between universes, 50 miles long, 35 miles high, and powered by a baby universe:
Yeah, it's pretty cool. Also, the Authority can call up a trans-dimensional "door" from anywhere to anywhere, which looks like a kind of swirly yellow rectangle hanging in the air, and can be used and abused in all kinds of creative ways.
As the development of the 20th century revolved around electricity, so do Jenny Sparks' powers. When she forms the Authority, she chooses some of the most powerful people in the world:
Jack Hawksmoor: A native of New York, Jack Hawksmoor spent a large amount of his childhood being kidnapped by aliens and experimented on. Massively unpleasant, it seems, but the systematic replacement of every internal organ in his body - and a few external ones, too - turned Jack into the King of Cities. He doesn't just thrive in them, he communicates with and commands them. It's pretty spectacular to see skyscrapers literally bend to someone's will, and even better when he uses his best power: cities as armour. An entire city. As armour. It's about as awesome as it sounds.
Jack becomes sort of the default leader whenever Jenny's not around - not that there's really a hard-and-fast leadership.
The Engineer: Angela Spica is actually the second Engineer - the first was a fellow scientist she vaguely knew, but she had no idea of his powers until he gave everything to her. Long story short, she replaced her blood with nine pints of nanotechnology that she can command at will with extraordinary results. She provides tech support and heavy artillery, and one of her best tricks is making multiple copies of herself, Dr. Manhatten-style, in order to multitask. She's no emotionless machine, though: she grew up collecting every issue of the DC comics, and even told her school guidance counsellor that she planned to be a superhero when she grew up. The Authority, then, is a dream come true for Angie - she gets to save the world and look awesome doing it.
The Doctor: No, not the one with the sonic screwdriver. Jeroen Thorndike is the latest in a long line of men given the collective magical power and knowledge of every previous Doctor, stretching back at least as far as the Jennies. That knowledge means being simultaneously aware of every human being, every dimension, everything - it's kind of an automatic empathy with the entire planet, which helps keep him from going mad with power. The Doctor also has access to the Garden of Ancestral Memory, where all the souls of previous Doctors reside for advice and guidance. However, unlike the Jennies, Doctors aren't born this way - a Doctor dies, and the title of Earth's Shaman passes on to someone else, in the middle of their otherwise ordinary life. In Jeroen's case, it was the life of a Dutch heroin addict, so these reality-altering powers are in the hands of someone who, shall we say, has a bit of trouble with the day-to-day superheroics. Nonetheless, Jenny Sparks manages to convince him onto the team, and its well worth it to see him collapse enemies into clouds of psychadelic butterflies and such.
Swift: Shen Li-Min, the world's greatest huntress, is a long-time friend of Jenny Sparks, and a former member of Stormwatch. Originally from Tibet, Shen is a Buddhist and a pacifist - sort of. Given that she's super-strong, super-tough, can grow wings and claws at will, hear her prey from the other side of the world, and is very aware that there is evil in the world that she can help eradicate, Shen's ideals of peace and pacifism often come into conflict with the utter bastards that the Authority have to fight. She balances it somehow, though, and remains a steadfast member of the team.
And then, there's Apollo and Midnighter:
Apollo: Solar-powered, super-strong, near-invulnerable, with burning eye-beams and a sunny disposition to match - if Apollo reminds you of a certain Kryptonian, it's not a coincidence. Apollo was the creation of Henry Bendix, a former Stormwatch Weatherman (best boss title ever) and, it turned out, a raging psychopath. Along with Midnighter and a host of other superheroes that bore a suspicious resemblence to members of the JLA, Apollo was part of a super-secret black ops team that got slaughtered on their first mission. He and Midnighter were the only ones to get out alive, and they spent five years on the run from Bendix, fighting evil from the shadows and sleeping in abandoned warehouses, until a new, saner Stormwatch picked them up and gave them their lives back. Did I mention that Bendix also totally erased their identities, leaving them with no real names or memories of their former lives?
Either way, Jenny Sparks plucked them out of 'retirement' not long after, and Apollo, at least, jumped at the chance. As you'd expect, he's a kind and optimistic person by nature, and it's rare to see him truly angry. He really believes in fighting for a finer world - and in his spare time, he watches bad sitcoms and soaks up the sun. The man's adorable.
Midnighter: If Apollo's an ersatz Superman, then it won't strain your brain to work out Midnighter's inspiration. There's little that's human about him, though - with large amounts of his body replaced by tougher stuff than flesh and bone, and computers in his brain that calculate the outcome of any confrontation a million times before the first blow is landed, Midnighter's the ultimate killing machine. For sheer bone-crunching, shuriken-throwing, limb-tearing badassery, Midnighter's your guy, and he'll do it with a sardonic quip and an evil grin. Also, a note: it's rare to see Midnighter without his mask, and when you do, no two artists can agree what his hair colour is. The Watsonian fanon surrounding this can get quite entertaining.
There's more to him than death, dismemberment, and ambiguous hair colour, though. He's good at killing, and he knows it, but to a select few people - primarily Apollo - he's fiercely loyal and loving. And suprisingly good with kids. Which is a good thing, because on the last day of 1999, Jenny Sparks dies... and a new Jenny is born.
Jenny Quantum: Born in Singapore on New Year's Day, 2000, Jenny Quantum's powers - which are, basically, anything she can think up - manifest immediately. Which is good, because she's immediately in trouble. Kidnapped for nefarious reasons, little Jenny is ultimately saved by the Authority, and with her parents dead along with most of downtown Singapore, Apollo and Midnighter decide to adopt her. The consequent levels of adorable badassery must be seen to be believed.
But Henry Bendix is a looming shadow, an evil machiavellian puppet master, and hey, it's a comic book - just because Jenny Sparks supposedly killed him stone dead doesn't mean he can't come back from somewhere. When Jenny Quantum is about four years old, Bendix manages to (very covertly) break up the Authority from within, even preying on Midnighter's worst insecurities to drive him away from Apollo and Jenny, back onto the streets. Skip forward four years, and the Authority is no more: Jeroen has died from an overdose, Shen has retreated to Tibet, Jack and Angie are cruising the Bleed for idle entertainment, and Apollo is raising Jenny alone. Then Jenny, who is already observant and cynical beyond her years, gets a visit from a future version of herself, advice from her previous incarnations, and decides to grow up and take charge, since the adults are clearly not going to.
She ages herself to fourteen, finds the new Doctor (a 16-year-old Palestinian suicide bomber named Habib Ben Hassan), drags Midnighter back home, exposes Bendix, and takes Jenny Sparks' old position as team leader. She also takes up smoking and swearing, but we can hope there's a few years yet before she starts drinking heavily. Note, though, that her habitual costume is a black leather jacket over a yellow t-shirt - a sweet callback to her dads.
Other significant characters include Henry Bendix (one of the only recurring baddies); Jackson King, a much saner Weatherman, and members of his Stormwatch team; and Kev Hawkins, a luckless British assassin who got his own (totally awesome) run of comics.
Apollo/Midnighter - almost goes without saying. They're married, with an adopted daughter, and are shown to be an extremely loving and loyal couple. They might be the best and most significant example of a gay superhero couple in comicdom, and the majority of fic and fandom (that I've seen) tends to centre around them.
Jack/Angie - in canon, Jack and Angie have a semi-serious-but-open, on-again-off-again, sex-based relationship that either party may or may not want to take more seriously. If it were a Facebook page instead of a comic, they would be each other's "It's Complicated."
Jeroen/Angie - they had sex once: she regretted it; he really, really didn't, and pined for her afterwards.
Shen/Jenny Sparks - apparently a couple, back in the day. We don't know much about it, but both ladies are bisexual and remain good friends until the end.
Jenny Quantum/Habib - small, but cute. She rescued him from Henry Bendix; he kissed her when the world was ending. They even have comparable powers, and are probably the most powerful superheroes on earth.
Here on LJ, there's theauthority, a comm for Authority fans with fic, news and monthly discussions as new issues come out. There's also quite a decent selection of Authority fic on Yuletide Treasure.
To give you a taste of what you're getting into, you might want to check out Scans_Daily and its "Authority" tag. It's a much smaller collection than the old scans_daily had, though, and not nearly as satisfying as reading the whole thing. If you just want a summary, though, there's a fairly in-depth overview at Comicvine.