Short answers, pulled from the story.
The first Dungeons & Dragons game was printed in 1974 with a production budget of only $2000. This meager sum forced co-founder Gary Gygax to recruit a makeshift team of friends and family to illustrate the pages for just $2 to $3 each.
The year 1977 marked a definitive split in the history of the game, dividing the original Dungeons & Dragons into two distinct branches that coexisted for over two decades. One side retained the original name as a rules-light system, while the other emerged as Advanced Dungeons & Dragons, a more complex system published between 1977 and 1979.
Wizards of the Coast released the third edition of Dungeons & Dragons in 2000, dropping the word Advanced from the title. This edition served as the basis for the broader d20 System, a role-playing framework built around 20-sided dice that unified mechanics and removed previous restrictions on class and race combinations.
The release of the fourth edition in June 2008 transformed Dungeons & Dragons into a purely tactical miniatures game focused on mechanical balance. This edition introduced a new power structure where all classes had similar at-will, per-encounter, and per-day powers, and extended core rules to level 30.
The fifth edition of Dungeons & Dragons was released in 2014, marking a return to the game's roots while introducing new mechanics to streamline play. This edition introduced a single proficiency bonus that increased as character level increased and the advantage and disadvantage mechanic to simplify conditional modifiers.
In September 2021, Wizards of the Coast announced One D&D, a backward compatible evolution of the fifth edition to be released in 2024. Revised editions of the Player's Handbook, Monster Manual, and Dungeon Master's Guide were scheduled to have a staggered release between September 2024 and February 2025.