Dragonlance is set on the world of Krynn. The majority of the novels take place in the various regions of Ansalon, a small continent, though some have taken place on the continent of Taladas, located northeast of Ansalon. The world's major gods are the High God and his children: good Paladine, neutral Gilean, and evil Takhisis. The gods are opposed by Chaos, who seeks to destroy Krynn. Depending on the time period, the evil chromatic and the good metallic dragons are rare or plentiful. Humans are Krynn's most common humanoid race, but elves, dwarves, kender, gnomes, and minotaurs occupy the world as well. Clerics derive magical powers from their gods, and wizards derive their power from the three moon gods, good Solinari, neutral Lunitari, and evil Nuitari. Hickman had previously served as a Mormon missionary in Java for two years, and uses Indonesian in Dragonlance spells. During Krynn's various wars, armies of draconians are used as troops. Draconians are created by corrupting a dragon egg, thereby creating a reptilian humanoid. Any dragon egg can be used to make a draconian, although the ones most commonly used are good dragon eggs because the evil kings want more evil dragons to hatch.
Other gods of the setting include the gods of good Branchala, Habbakuk, Kiri-Jolith, Majere, and Mishakal; the gods of neutrality Chislev, Reorx, Shinare, Sirrion, and Zivilyn; and the gods of evil, Chemosh, Hiddukel, Morgion, Sargonnas, and Zeboim.
The history of the world of Krynn, and thus the settings for both the novels and gaming supplements, is roughly split into five separate ages. The first age is the time of creation, when the gods are born and Krynn is formed. The Age of Dreams, the second age, is marked by the rapid growth of the world's first great civilizations and the appearance of myriad new races. This era is also marked by three great wars between dragons and their minions. Following the Third Dragon War, in the Age of Might, the Cataclysm obliterates the great empire of Istar and changes almost the entire surface of Krynn. A three-hundred year depression follows this event, in what is called the Age of Despair. This period also marks the War of the Lance. When Dragonlance was first introduced to Dungeons & Dragons, events such as the Lost Wars happened during The Age of Despair. Later Age of Mortals novels and game supplements took Krynn into the Fifth Age (the Age of Mortals).
Source: Wikipedia, "Dragonlance", available under the CC-BY-SA License.