An atlas is a book or collection of maps. Many atlases also contain facts and history about certain places. There are many kinds of specialized atlases, such as road atlases and historical atlases. There are also star atlases, which give the location and placement of stars, planets and other celestial objects.

Besides showing maps of all the countries and continents, a world atlas may also provide facts about the countries. Individual maps of major cities or other points of interest may also be included in a world atlas. Population statistics, the location of natural resources, cultural and religious information and political data are frequently found in an atlas.

Although people have been using maps for thousands of years, civilizations really didnt begin producing large atlases until the 1500s. During this time, European and Asian countries were exploring the world through trade and colonization. They depended on atlases to guide them through unfamiliar territory. As European explorers mapped the "New World" (the Americas), they also updated atlases with their discoveries.

In 1595, a collection of maps prepared by the Flemish mapmaker Gerardus Mercator was published with the word "atlas" in the title. Atlas referred to a portrait of King Atlas, a mythical African monarch. King Atlas invented the first celestial globe. A celestial globe is a ball-shaped map of the stars and constellations. Celestial globes were very important in navigation, when sailors used stars to determine their position at sea. Mercator showed King Atlas to demonstrate his importance to navigation. This was the first time the term was applied to a collection of maps. Eventually, "atlas" came to be used for any book of maps.