The fifth edition of D&D collected on the popularity of fourth edition. Its flagship product was the Rules Cyclopedia, which consolidadated and improved the rules scattered throughout the four rules sets and the gazetteers.
Basic Rues: This rulebook provides all of the basic rules of the game such as character generation for clerics, elves, dwarves, fighters, halflings, magic-users and thieves. It also provides equipment, spells, treasure and monsters appropriate for first through fifth level characters. Basic rules required for dungeon-level adventuring is covered.
Rules Cyclopedia: This hardback volume contains all of the compiled rules from 4th editions basic through master sets as well as the general skills from the gazetteer series. These rules are further refined to eliminate flaws in the previous edition.
Wrath of the Immortals: This boxed set covers everything that players need to run immortal-level characters and campaigns.
Creature Catalog: This book gives the Dungeon Master even more monsters to use in his adventures.
Champions of Mystara: This boxed set compiles the adventures of the Princess Ark from Dragon magazine in the regions of Hule, making this the gazetteer for the Hule region. It is notable for providing rules for travel in the void of space and the construction of skyships.
Thunder Rift: This is a new setting intended for use by basic level characters (levels 1-5). When they outgrow the setting they find a way out of the rift and into the DM's world of choice (usually Mystara).