second (or more) class at a specific point defined by the first class, a concept generally called multiclassing. In the 1st and 2nd editions, changing a character's class is difficult. Only those playing as humans can, and it requires extremely high stats to do so. This is called "dual-classing". Non-humans, on the other hand, can "multiclass" where they effectively learn two (or rarely even three) classes at the same time at the cost of a slower character level progression. The 3rd edition allows players to mix and match levels from any number of classes, though certain combinations are more effective than others. In addition, Prestige classes add more options for multiclassing. This edition offers the most freedom regarding multiclassing. There are, however, penalties to the rate of experience point gained if classes are added haphazardly. The 3rd edition version of Unearthed Arcana includes rules for gestalt characters which combine the advantages of two classes. The 4th edition allows characters to take a feat that grants access to specific facets of another class. The class-specific multiclass feats are also prerequisites for the power-swap feats, each of which allows the character to swap out a daily, encounter, or utility power from their first class for one from their second class. Also, at level 11, a character with a multiclass feat and all of the power-swap feats is eligible for paragon multiclassing, which allows them to gain additional powers from their second class in lieu of taking a Paragon Path. Some classes are only available through multiclassing; the first such class was Spellscarred, introduced in the Forgotten Realms Player's Guide. In the 4th Edition, each character can only multiclass into a single class, unless otherwise stated by their primary class (such as the Bard). The Player's Handbook III introduced "hybrid" classes, a deeper form of multiclassing in which elements of two classes are combined each level. In the 5th edition, multiclassing requires minimum ability scores before it can be chosen; however, the requirements are not as steep as in previous editions. The core classes only require an ability score of 13 or greater in the specific requisite score, except for the Monk, Paladin and Ranger (who need 13s in two stats). Classes by editions Original Dungeons & Dragons In the original Dungeons & Dragons boxed set, there were only three main classes: the Cleric, the Fighting man, and the Magic-User. The first supplement,