When Marvel’s The Avengers went on to become the third highest grossing film of all time, Warner Bros. had the expected response of proclaiming their determination to get a Justice League film into production as soon as possible.

To many this seemed a foolish and imitative attempt to rake in Avengers-like money without putting in the kind of groundwork that Marvel did in establishing its cinematic universe. Many argued that what WB should do, instead, was a film featuring the one thing that Marvel did not have: a team-up of their two most iconic characters, Superman and Batman. In the end, of course, that’s exactly what’s happening with the sequel to Man of Steel bringing together Henry Cavill’s Superman with Ben Affleck’s Batman. And while a direct sequel to the first film would have been preferable, there’s a genuine sense of excitement about seeing these two characters appearing together in a live action adventure for the first time. Superman and Batman coming together, of course, is nothing new in other mediums.

“We start at the beginning, and the beginning is New York World’s Fair Comics, 1940 edition, and the cover of that which was the first one that showed Superman and Batman in a scene together,” enthuses Michael Uslan, emphasizing that he’s speaking as a comics historian and fanboy and not as the producer of every Batman film since Tim Burton’s 1989 effort. “These are two characters who might, at first blush, look very similar, but are in fact very different. When Bob Kane and Bill Finger created Batman, the idea was, ‘Okay, Superman’s the first superhero who’s incredibly popular, sales are beginning to skyrocket, we gotta create the second superhero, so let’s go in the opposite direction. Let’s create someone who’s human. A superhero with no superpowers.’ There’s the divide.

“The second part of it,” he continues, “is that Superman is an alien, he comes from another planet. He has been sometimes perceived or portrayed as almost messiah-like with the degree of his powers. Batman is an everyman. He is the figure that I fell in love with as a superhero more so than Superman, the Hulk or any of them, because he was human. And because that identification was so strong, and I did believe when I was eight that if I studied hard, worked out hard and my dad bought me a cool car, I could be this guy. It’s that identification that’s really strong and helps Batman in his other media appearances cross borders and cultures.”

Superman and Batman began to crossover with each other on the Man of Steel’s radio show in the 1950s, sharing adventures in the pages of World’s Finest for decades, both being members of the Justice League in print, animation and video games; and both the stars of Greg Pak’s run on the Batman/Superman comic. It seems that they remain, even after all of these years, an endlessly fascinating combination of personalities who, on the surface, couldn’t seem more different from each other, yet are united on so many fronts.

“The list of qualities that keep the two characters diametrically opposed is huge,” offers writer Mark Waid, a veteran of Justice League, Superman: Birthright and Kingdom Come, among many others. “Batman was born from a moment of rage and grief and helplessness. Superman was born from tragedy as well — but a very emotionally removed tragedy, and one that was ultimately about hope and promise and about the continuance of life. Both characters have secret identities and wear masks, but Bruce Wayne’s mask is Batman while Superman’s mask is Clark Kent. One’s posing as something superhuman while the other is pretending to be absolutely normal. While Batman is all about fear and intimidation, Superman is a very relaxed, open, friendly figure — he deliberately doesn’t wear a mask, because he knows he has to earn people’s trust and when you’re impervious to harm, there’s no reason not to be relaxed in your movements and body language.

“But what draws them together,” he adds, “is a mutual thirst for justice and fairness. Batman is, in his heart of hearts, always trying to make sure that what happened to him as a boy never happens to anyone else; Superman was raised with a phenomenal respect for human life and is as vulnerable as anyone when it comes to striking at him through his heart and compassion.”

Actor Kevin Conroy, who has been voicing the Dark Knight on and off since the 1992 premiere of Batman: The Animated Series, has his own views on the character dynamics between Batman and Superman. “Batman’s isolation and his singularity, his inability to really let other people into his personal world, is really essential to the character,” Conroy muses. “It’s part of what audiences expect. Even in a series like Justice League, where he was one of seven superheroes, Batman was always the odd man out. The others would go off as a group to do something — you know, they might go have pizza — and Batman was always the guy left back in the cave. So in these stories in which he is teamed with Superman, I think it’s the closest Batman gets to have a brother, a kindred spirit. Superman understands Batman. He understands his need to be alone and his isolation. He’s probably the only one of all the superheroes who can balance Batman in terms of wit and power, so they’re a very good balance for each other.”

As to what it is that Batman sees in Superman as a person, he reflects, “I think Batman thinks of Superman as the Dudley Do-Right of superheroes. He admires his strength and his character, but he also thinks he’s incredibly naïve and very unsophisticated about the world. Remember, Batman is also Bruce Wayne, so he’s very urbane. He’s very versed in the way of the world. And Superman is Clark Kent. That’s where I think the distinction is. Batman just thinks that Superman is kind of a very, very naïve guy who always sees the goodness in everybody. And Batman tends to see the darkness.”

“I think Superman likes Batman,” interjects actor Tim Daly, who voiced the character in Superman: The Animated Series and has worked with Conroy as Batman numerous times over the years. “In his own private way, he gets a kick out of the fact that he can count on Batman being cynical and pessimistic, and that he sort of relies on that probably in the way you rely on certain friends or family members to do certain things that you shake your head at and go, ‘Oh, jeez.’ It’s sort of comforting. He’s come to trust Batman to have his back. And he has a genuine concern for him.”

Author Kevin J. Anderson, who wrote the Superman/Batman novel Enemies & Allies, feels that those two characters together make something akin to a bromance novel. “In every romance novel,” he poses, “the team has to hate each other at first, they fight, and they finally figure out that they were meant to be together. It’s almost like that with Batman and Superman. They are always fighting and arguing and resisting each other’s efforts to do something, because they’re pretty set in their ways. Kal-El does not want to beat up the bad guys, he just wants to take them to jail. Batman, of course, says, ‘If they get bruised because they were trying to mug somebody, then they asked for it.’ It’s just a different attitude they have. It’s interesting to have the two of them together, because it allows you to compare and contrast.”

Part of that, according to director Jay Oliva (The Dark Knight Returns, Justice League: The Flashpoint Paradox, Justice League: War), comes from their background. “Depending on the canon,” he suggests, “Superman loses Pa Kent and that is kind of the catalyst to make sure that Superman upholds all of the things his ma and pa taught him. Batman on the other hand doesn’t really use what Thomas and Martha Wayne taught him. He uses their death as a way to kind of clean up Gotham and do things that the police can’t. Their similarity is that they’re both good guys who want to make the world a better place, they just have different ways of doing it.”

With a laugh, Daly explains that he views the Superman-Batman team-ups as something akin to a buddy film. “”When you think about great buddy films,” says Daly, “like Butch Cassidy and the Sundance Kid, these guys are willing to die for each other, and yet they’re constantly giving each other a hard time. And they frustrate each other to no end. Think about a movie like 48Hrs. Ultimately that’s a buddy film, but it starts out with Nick Nolte and Eddie Murphy beating each other up and abusing each other in all kinds of different ways. Superman and Batman are kind of like that: the oil and water who become inseparable.”

Though the road to get there isn’t always easy, notes Greg Pak whose stories take place in DC’s New 52 when the characters are early in their careers. “Thematically,” says Pak, “I think this is about two heroes challenging each other every step of the way, pushing each other. It’s about two rivals challenging each other to become better heroes; to learn how to become heroes, really. It’s through their conflict they have with each other that they figure out what it is they’re supposed to do. I think that’s endlessly interesting. Neither one of these guys has all of the answers, even though he thinks he might. When you put them together, and bounce them off of each other, see them help and injure each other, each one of these guys is figuring out how to be a hero.”

In some ways there would seem to be such a vast chasm between the characters as people, that the question becomes what it is that they fill in each other that, together, makes them such a complete crime-fighting entity? “They’re both superheroes, so they share that in common,” says Daly. “They understand and forgive the other one for living a double life, because they both essentially have to do it. And more often than not they’re on the same side. Batman, despite his darkness, is essentially a power of good. It’s kind of like sometimes you wonder why big movie stars are best friends with huge movie stars. I think the answer is that they live such a specific life that’s so odd and so difficult, that they tend to gravitate toward people who have an understanding of that and forgive the fact that they have to be private or have to wear disguises, or come in the back door of the place so there’s not a big fuss made over them. I think that’s sort of the same kind of relationship for Batman and Superman.”

For Mark Waid, a lot of the answer comes from the fact that Superman is largely guileless. “He’s honest,” details Waid. “He knows that his entire existence and acceptance by mankind as a friend and not an enemy requires him to be trustworthy, and he smiles. Batman realizes that having someone like that on your side, able to work in the sunlight, is an asset — not just because of his powers, but because there are moments during a crisis when you don’t want the people you’re trying to help to fear you. And Batman genuinely likes Superman, because while their methods differ, Batman respects someone who is as dedicated to the cause of justice as he is, and he respects the depth of personal sacrifice called upon for a Superman.

“But one of Superman’s natural shortcomings,” he elaborates, “is that he can’t think like a criminal. He just can’t. That doesn’t make him stupid or simple — he just has a natural blind spot when it comes to understanding abnormal, anti-social behavior because he’s so trained in being selfless that he can’t put himself in the shoes of someone whose motives are purely selfish. And while he’s an optimist, he’s a realist, too. He understands that there are many, many dark and corrupted men and women who live in the shadows and prey upon the weak, and it takes someone like Batman to help him comprehend what motivates them, how they think, and how they’ll act next. Superman’s in his element when he’s dealing with in-your-face threats or external cataclysms; Batman excels at criminal psychology.”

Oliva raises an interesting point in that he believes Superman and Batman’s approach to crime and the world at large has a lot to do with the potential span of their lifetimes. “Superman, depending on canon, is immortal and Batman has a finite amount of time,” Oliva explains. “He starts fighting crime in his ’20s, but as we know when you get to The Dark Knight Returns, he’s in his ’60s or ’70s. There’s only so much he can do. In Batman’s mind he’s got a timetable: ‘I’ve only got X amount of years to continue doing this,’ and in those years he’s got to do a lot. Superman, on the other hand, kind of sees the bigger picture: ‘I’m going to be here for a very long time. I’ve got to think things in order so the world doesn’t end during my watch.’ He has to try to shepherd us or lead us or protect us into the centuries to come. I think that’s a cool dynamic. You’ve got a guy who’s an immortal and another one that’s mortal, so they have very different timetables. It’s why Superman is patient and tries to work things out, and Batman says, ‘Screw that. Let’s do this now.’ They kind of play off of each other that way and they respect each other. They help fill in what the other ones needs.”

“They do sort of composite,” says writer Alan Burnett, who has been involved with the DC Tooniverse since the later incarnations of Super Friends and currently serves as supervising producer of the DC animated films. “One looks on the dark side, the other the bright side. One is continuously suspicious about humanity, the other one is a beacon. One comes from a back alley, the other comes from the cornfields. Those differing points of view fill the gap between them.”

Which in turn creates the dynamic between them that will result in 2016’s first live action meeting between the two iconic characters, representing something of a dream come true for many, Michel Uslan among them.

“When I was a kid growing up, the first issue of World’s Finest comics I bought on the stand was issue #99,” he says. “I loved when Batman and Superman got together for whatever reason, because it was exciting. This has been a part of my growing up. A part of my world. A part of my personal mythology. How could I not be excited?”