Krakatoa: The Day the World Exploded was published in 2003 and written by British-American author Simon Winchester. The book is a work of historical nonfiction, exploring the 1883 eruption of the volcano Krakatoa, which the book is named after.

Krakatoa, which is located in Indonesia, is a caldera, meaning it is a large hollow land formation shaped like a cauldron and formed by previous volcanic events. The eruption in 1883 triggered a tsunami that further devastated the island. Krakatoa has long been known for volcanic activity; however, a series of four eruptions in May of 1883 were some of the most violent, with aftereffects of steam, ash, and shaking observed until August that same year. The eruptions triggered lava flows, which, combined with volcanic ash in the air and the tsunami, resulted in a high death toll of at least 40,000 people.

This 1883 eruption had effects worldwide, not just on the island. Winchester's approach to Krakatoa's eruption and annihilation of the island of the same name in the waters near Indonesia has been lauded as being multifaceted and as demonstrating the intertwined nature of the eruption's effects. He includes many aspects and details tied to the horrific event. The explosion was heard as far away as Australia and India, according to Winchester, with volcanic ash and large waves experienced even in France.

Winchester also includes the political side to Krakatoa's explosion. Post-eruption, on the nearby island of Java, a movement of anti-Western Muslim protesters broke out. This triggered one of the first noted outbreaks of Islamic fundamentalist killings in the world. Winchester looks at how this political event is tied to Krakatoa's explosion. The book's title, The Day the World Exploded, has deeper meanings than just a volcanic eruption.

Krakatoa: The Day the World Exploded was an international bestseller, largely in part due to Winchester's in-depth and varied look at the catastrophic and deathly crisis. He examines the eruption from multiple angles and dimensions, giving us as readers a deeper view of one of the most devastating natural disasters ever recorded.