from the back cover:
Unlock A Wellspring of Knowledge
This supplement presents an inexhaustible source of new rules to introduce into your Dungeons & Dragons game. Inside are ideas, options, and alternates to the standard D&D rules you can choose from to fit your campaign's style of play. From variant classes, races, feats, and abilities to alternate spellcasting systems, combat and campaign options Unearthed Arcana offers a tremendous array of material for you to explore.
Expanded by;
Unearthed Arcana Variant Checklist