OK, so I'm going to go through every edition of D&D, when it was made, and toss some interesting little facts in for flavor, and my own hot takes of course. Listed in chronological order, comments aren't in chronological order. Some preconceptions may be diverted, and some things possibly learned if you didn't already know:
1974 Original D&D AKA OD&D, Brown Box D&D, White Box D&D
Came out originally in a brown box put together by Gygax himself in his basement. There's only something like 100 of these in circulation, zealously guarded by collectors. Later reprinted in a white box and then later reprinted again to take out Tolkien references (Hobbits, Ents) when the estate threatened to sue. When WotC brought out a lavish wooden box edition in 2013, I bought it and wondered if they'd have the balls to ask the Tolkien estate to be able to produce the originals. Of course they didn't because WotC didn't do anything right with the classic reprints (and this will come up again). The original edition only used a d20 and a d6, and it isn't fully playable by itself, expecting the owner to also have copies of Chainmail (war game) and Outdoor Survival (board game)
1977 Holmes Basic AKA Blue Book D&D (AKA Original D&D for morons)
Came out a few years later, meant to be an easy introduction into D&D, written by Eric Holmes. This is the edition I know the least about, I have a copy and could only really tell you that apparently Eric took some liberties that ejected him from TSR as these are his only credits that I know if. The only shocking thing I found was rolling to hit for Magic Missile. The product was intended to be a starter set for bringing in people for Advanced Dungeons & Dragons 1E, which came soon thereafter and was already being written. In the 70s it was a pain in the ass to produce corebooks, it took YEARS to get them ready for printing. My copy is the second edition from 1978, if the text is unchanged then this was the first edition to have two-axis alignment system. As an intro product, you could only reach 3rd level with the rules herein. Some really seem to enjoy this edition of D&D, there are at least 3 products I know of that exist to extend this edition into something more full-fledged.
1978 Advanced Dungeons & Dragons AKA First Edition
The Monster Manual actually came out a year earlier, and so it's math was actually more aimed at Original D&D, which had several supplements by now adding different die types, the thief class, etc to it. The second printing of these books brought us the classic orange spine look of D&D, and while I like David Sutherland's iconic cover, Jeff Easley's art is D&D to me so I was annoyed by the D&D reprints using the original cover art. I found some solace in the fact that when they did the second edition later, they would at least use the good layout there. Right? Anywho, this is the last edition that Gygax has legitimate writing credits on.
1981 Basic/Expert D&D AKA B/X D&D, Moldvay Basic
Seemingly the most beloved old school D&D game, this was the first game to have unified Race/Class or what some call a Race as Class system. Like Holmes the basic set let characters level to 3rd level, unlike Holmes B/X got an expansion in Expert which allowed characters to get all the way to 12th level. The original Basic came in a boxed set with one of the best adventures ever produced, B2 Keep on the Borderlands.
1983 BECMI D&D AKA Mentzer D&D, Mentzer Basic
For reasons that could only be money related Mentzer took over for Moldvay and reproduced a "D&D Basic" set for the third time in less than a decade. This one was built much more in a "starter box set" mindset than a full game system in it's own right, and had five boxes in total before it was over - Basic, Expert, Companion, Master, Immortal. Hence BECMI.
1989 Advanced Dungeons & Dragons 2E AKA Second Edition, Pretty Second Edition
Multiple different reasons for this edition to come out when it did, Gygax was on the rocks with the company having Oriental Adventures basically ghostwritten for him by the same person who eventually penned this version, Zeb Cook. Likely the company wanted corebooks they didn't have to pay extreme royalties to Gygax for, and needed an injection of new talent as AD&D1 was and is cumbersome to read. Pressure from MADD caused a few things to change in this edition, all the demons and devils were renamed, and half-orcs and assassins were basically deleted. That being said this edition is where all the good settings came out, basically because management didn't give a fuck about creative any more, and thus didn't really oversee the dept. Birthright, Dark Sun, and Planescape fans can appreciate this fact. None of these settings used the whole damn salad bar of options available in D&D and were far better for it.
1991 D&D Rules Cyclopedia AKA BECMI Revised, One Book D&D
One of the other much hearted editions is this, I'm assuming it exists because they thought they'd get corebook benjamins for it. Sadly because it sounds like the title of a dictionary I don't think it sold very well when it initially came out. Otherwise it's what many consider to be the best version of BECMI, some even consider it the best iteration of race-as-class. Personally I didn't love it, partially because it has hundreds of pages of errata compiled by fans.
1995 Advanced Dungeons & Dragons 2.5 AKA Second Edition Revised, Ugly Second Edition, the most flammable version of D&D (It's possible only I use these last two).
This edition is so ugly it hurts, and the only corrections/errata I've ever seen to justify it's existence are corrected in both of my copies of Pretty Second Edition. I am almost positive they paid for Jeff to do new cover art (or possibly I think he was a staff artist at the time), tossed a couple bucks at random and terrible interior artists, and had somebody's idiot cousin do the layout. The text is virtually identical to Pretty Second Edition but the layout makes it impossible to penetrate. Basically I'd be ashamed if I had anything to do with this work. Easley's covers for this set aren't even very good. So this was a plain and simple cash grab by TSR. They spent years on their last legs before this started and had a few more years before turning it all over to WotC. This was essentially TSR going out with a whimper. So of course when WotC came out with their premium reprint years later, they used this dumpster fire edition instead of using the far, far better version that came before. I assume this was because they didn't want to actually have people begin enjoying a 20-year-old edition of the game. I know if this only-a-mother-could-love-but-still-would-put-up-for-adoption version of the game were my first PHB, I wouldn't even be a roleplayer at this point in my life. The Monstrous Manual was virtually unchanged between editions, so I own original and Premium Reprint of that book. While much of this list is second hand or learned experience, here and beyond this point I actually lived through, and much of it online.
2000: Dungeons & Dragons 3E AKA Third Edition, Three Point Oh
The best and worst thing to ever happen to D&D. By itself the ruleset isn't complete trash, but it's really a small thing in comparison to the OGL at the end of the book. The Open Gaming License, which created a bubble that eventually burst, it was a hail Mary to try to get D&D to own the entire universe of roleplaying games, instead of the mere 60% or so it owned up until that point (yes even the Vampire boom was softening at this point, and never really felt at my physical location). And honestly by 2005 they were pretty close to owning the entire market. The best thing out of the OGL is the OSR. But that didn't happen yet.
2003: Dungeons & Dragons 3.5 AKA Third Edition, Three Point Five, Three Point Ecks
A bunch of semi-unnecessary revisions and modifications with a tinge of actual errata, basically this edition existed because the last one was built without any good playtesting. But why revise and release errata when you could instead produce the fucking corebooks all over again and force everyone who plays D&D to repurchase them? This stupid bullshit was another blatant cash grab and the true catalyst to the OSR. It also existed to try to restart the d20 bubble but instead it just invalidated the shit that came before and cemented the d20 glut of shit in the market that nobody was fixing and there was no quality control of. Eventually the d20 bubble burst at about 2007 or so when everybody heard 4th was coming out. At that point lots of tiny companies died and while a couple players survived (Goodman games, Mongoose, Green Ronin), the vast majority floundered and died, other than those bringing out OSR material. This is the first "fuck you" edition of the game I actually lived through while aware of the greater hobby, having started late enough in 2E that 2.5 was already out and being young enough to not know what the fuck was going on at all. I never bought 3.5, I felt betrayed by it's existence and went into the indie scene about this time looking for alternatives. I didn't buy the reprints either, because why would I?
2008: Dungeons & Dragons 4E AKA Fourth Edition
I won't say much about this edition save that it was the natural progression of where 3E was headed, and was indeed a board game system dressed up as a RPG. A very cleanly designed, to the point of blandness, complex war game-like board game system where the design gives zero fucks about your character or the fantasy world at large. Gloomhaven cares more about characterization and the world at large than D&D4E and it's an actual fucking boardgame. It only cares about how your minifigs deal with being in relation to other minifigs on a battle mat (don't bring up skill challenges because I'll liken them to quicktime events in videogames and you'll lose your shit and the argument at the same time). Now that I say all that let me say this again - this is 100% precisely where 3E was headed, and a completely natural evolution of the ruleset. Many people played 3E this way even, but the system wasn't as good as the one presented here for this playstyle. In this way 4E is better designed than 5E, which is better designed than 3E. The only problem with 4E was it didn't really support a D&D experience as we knew it for the 30 years of the hobby up until this point. Even on 3E's worst day, the DM makes meaningful decisions. 4E disallows this by design because as a fallible human, the DM isn't considered safe hands to put the play experience in by the ruleset. The DM basically went from (using a courtroom analogy) being the judge and jury to being an attorney, worse he was both attorneys, pleading his case and hoping the ruleset made the right decision. Maybe it did. Maybe the game was better for some players. Maybe the stress of being the judge was too much for some DMs. But not me.
2014: Dungeons & Dragons 5E AKA Fifth Edition
I thought the OSR won the edition wars when this came out. I was ecstatic, I bought every book, losing more and more enthusiasm until Wildemount was announced and I said "No more of this shit". Then a close friend of mine got it and liked it so that became my last D&D purchase. And I'll be honest, the deity sections of that book aren't awful. I don't remember much else of it.
I've receded back into the indie scene and OSR now. Back to where content creators aren't bowing to corporate overlords. Back to where you can have a supplemental book where an elven pleasure-city can have a giant statue of a woman playing with herself. I want to promote products that are creative, interesting, shocking, and raw. Where I know the author's artistic vision wasn't compromised by what other people want or whether public opinion will seek to cancel them.
EDIT 3/30/2025
2025: Dungeons & Dragons 6E AKA Sixth Edition, D&D 2024. D&D 2025, Fifther Edition, 5.5, 5.24, and about a jillion others.
Well, to those of you new to the edition change, I must say... First time? The 5E players I know aren't switching. Since the VTT is dead, and that was the catalyst for this even existing, I'm expecting it to be the first failed-out-the-gate edition. The inclusion of so many soft rules that ruin the concept of player choice like an entire chapter of the DMG devoted to immutable video-game-esque home-base camps has terminally cucked the game. There are idiots out there who will say "this is exactly like 5E" If it was, there wouldn't be a distinction dickface. The concept of race has been eliminated form the game entirely, along with it's bioessentialism. This is because terminal liberal blue-hairs on X think that fantasy and reality are the same thing, which is how they believe people who were born with penises can be considered women. This is the game for them, but funny enough there are still alignments, both character and monster alignments. So not every traditional element that they hate has been striken out. The fun part is that this is not a game for gamers but at the same time all this game's target audience... don't buy RPGs. I'll talk more about this in a later post.