>>1820797
Honestly, Batman: Year One is pretty boring and overrated, and comes off feeling like a Gordon story more than a Batman story. But of course if you want to introduce an absolute normalfag, then starting with the origin story is a good idea. If I was recommending a Batman comic to someone who already knew and liked Batman adaptations (so basically most males, but practically no females), then I'd go for The Dark Knight Returns. Year One is practically a prequel to it, and it explores the character with much more depth. Of course, I think it doesn't quite understand Superman properly, and contributes to some casuals who have dipped their toes into comics but not gone very far misunderstanding Superman, but it's a Batman comic, so I don't care too much. Also, it still sort of gets Superman. It doesn't completely ruin him like many works influenced by or even adapting The Dark Knight Returns have done.
Of course even a casual, let alone a damn professor, should realize that it's hard to say there is such a thing as a "definitive Batman comic." The character is so varied, with so many interpretations, even if you stick solely to main canon. Tone changes so wildly over the decades, and the different tones are all beloved, and that variability is a big part of why the series is so successful. Plus, for many decades now, most stories have been very long multi-part arcs that only make sense if you already know a great deal of information from previous stories. Even defining a single story is difficult in the last 40 years, and when they can be easily defined, they're often very long and even then still rely on years and decades of continuity.
DC marketed the New 52 as a "reboot" so casuals felt like they could jump in, but actually it was halfway through Grant Morrison's run, which is a favorite but is many years long, and is based upon the premise of calling back to basically every Batman story ever and reminding readers that they're all canon. Even the non-Morrison New 52 Batman comics, like the well liked and successful Court of Owls storyline, not only takes place at the same time as the Morrison stuff, and expects you to understand who dozens of pre-existing characters are, but actually is referencing and adapting previous stories about characters and concepts like Owlman and Thomas Wayne, Jr., who each go back many decades. You can understand the plot without knowing them, but you won't understand the full significance of the story.
Or maybe you want to read Knightfall, a very famous story that has led to many adaptations. Okay, you're expected to know who Batman is, but everyone knows that. Also basically every Batman villain ever shows up and does important stuff, but okay, you know guys like Joker and Catwoman and Two-Face and Riddler, so you can get most of that. It's the first appearance of Bane, but actually Bane is just a villain who uses a pre-existing drug called Venom, which is basically super-steroids, but to understand the significance of that and why it's such a big deal, you're supposed to have already read the previous Batman story where it was introduced a few years earlier. And Robin is important, but you know Robin. Did you know that in this story Batman is on his third Robin, and the first is grown up and has a different name now, and the second one is dead? You're expected to understand and care about these characters quite a bit. Did you know Superman was dead when this story happened?
Wait what? You're wondering how Superman died? Better back up and read the whole Death of Superman arc, which Knightfall is a blatant ripoff of, meaning it's just as long and complicated. But even that story begins with Lex Luthor secretly being in a clone body which he is passing off as his own son, who is fucking Supergirl, who isn't even Superman's cousin, but a psychic goo monster from something called a "pocket universe." Also there's a bunch of stuff about underground mutants and something called Project Cadmus. Want to understand that? Just go back to the '70s and read all of Jack Kirby's Fourth World, the epic magnum opus of comics' greatest creator which spanned four different ongoing comic series, and not only spins out of the solo series of "Superman's Pal: Jimmy Olsen," (so you'd better be somewhat familiar with him), but heavily references stories Kirby did back in the '40s about The Newsboy Legion and The Guardian, essentially bringing them back and acting as a sequel series. What, you don't know the super famous characters of The Newsboy Legion? Just go back to the '40s and read all their comics, and you'll figure it out. Then you can finally understand Knightfall.
Oh wait, I forgot about how Green Lantern, and the end of the entire Green Lantern series, is so important to The Death of Superman. Okay, so first you have to understand that there are 3600 Green Lanterns...
You honestly have to be very, very uninformed to not really realize the stupidity of even asking for "the definitive Batman comic." The very question barely makes sense. But of course these women didn't become professors because they were actually experts in their fields, they became professors because they were women and would get pushed ahead despite not having even casual knowledge of the field.
And yes, I know the absurdity of complaining about this after saying I'd recommend The Dark Knight Returns, a story which takes place in the future and expects you to understand Batman continuity up to the mid-1980s pretty well, including things like Jason Todd. But I'd only recommend it to men, since they already understand most basic Batman characters and concepts, and they're probably casual enough that, since Nightwing doesn't show up, they will either understand who Jason Todd is, or not realize there are two Robins in the first place, so they won't be confused.